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#include <bits/stdc++.h>
#include <cstdint>

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;

//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set; // set
//typedef tree<pair<int, int>, null_type, less<pair<int, int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set; // multiset  {element, time}
// order_of_key(k)      find_by_order(k)

#define FAST_IO ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define fi first
#define se second
#define nl "\n"
#define as " "
#define rep(i, l, r) for(ll i=l;i<r;++i)

#define sum(a)     ( accumulate ((a).begin(), (a).end(), 0ll))
#define mine(a)    (*min_element((a).begin(), (a).end()))
#define maxe(a)    (*max_element((a).begin(), (a).end()))
#define mini(a)    ( min_element((a).begin(), (a).end()) - (a).begin())
#define maxi(a)    ( max_element((a).begin(), (a).end()) - (a).begin())
#define maxij(a, i, j)    ( max_element((a).begin()+i, (a).begin()+j+1) - (a).begin())
#define lowb(a, x) ( lower_bound((a).begin(), (a).end(), (x)) - (a).begin())
#define uppb(a, x) ( upper_bound((a).begin(), (a).end(), (x)) - (a).begin())
#define sz(a)      (int)((a).size())
#define rs(a, n)   ((a).resize(n))
#define ms(a, val)     ( memset((a), val, sz(a))

//debugging
#ifndef ONLINE_JUDGE
#define dg(x) cerr << #x << "\t"; _print(x); cerr << endl;
#define dg2(x, y) cerr << #x << "\t"; _print(x); cerr << "\t|\t" << #y << "\t"; _print(y); cerr << endl;
#define dg3(x, y, z) cerr << #x << "\t"; _print(x); cerr << "\t|\t" << #y << "\t"; _print(y); cerr << "\t|\t" << #z << "\t"; _print(z); cerr << endl;
#define dg4(x, y, z, w) cerr << #x << "\t"; _print(x); cerr << "\t|\t" << #y << "\t"; _print(y); cerr << "\t|\t" << #z << "\t"; _print(z); cerr << "\t|\t" << #w << "\t"; _print(w); cerr << endl;
#define dgsq(x) { cerr << #x << "\n"; for(int i=0;i<sz(x);++i) {_print(i); _print(x[i]); cerr << "\n";} }
#else
#define dg(x)
#define dg2(x, y)
#define dg3(x, y, z)
#define dg4(x, y, z, w)
#define dgsq(x)
#endif

void _print(int x){cerr << x;}
void _print(float x){cerr << x;}
void _print(double x){cerr << x;}
void _print(string x){cerr << x;}
void _print(ll x){cerr << x;}
void _print(ull x){cerr << x;}
void _print(char x){cerr << x;}
void _print(bool x){cerr << x;}
template<class T,class V>void _print(pair<T,V> x){cerr << "[";_print(x.fi);cerr << " ";_print(x.se);cerr << "]";}
template<class T,class V>void _print(unordered_map<T,V> x){cerr << "[ ";for(auto i: x){_print(i);cerr << " ";}cerr << "]";}
template<class T> void _print(set<T> x){cerr << "[ ";for(T i: x){_print(i);cerr << " ";}cerr << "]";}
template<class T> void _print(multiset<T> x){cerr << "[ ";for(T i: x){_print(i);cerr << " ";}cerr << "]";}
template<class T> void _print(priority_queue<T, vector<T>, greater<T>> x){cerr << "[ ";while(!x.empty()){_print(x.top());cerr << " ";x.pop();}cerr << "]";}
template<class T> void _print(priority_queue<T> x){cerr << "[ ";while(!x.empty()){_print(x.top());cerr << " ";x.pop();}cerr << "]";}
template<class T> void _print(queue<T> x){cerr << "[ ";while(!x.empty()){_print(x.front());cerr << " ";x.pop();}cerr << "]";}
template<class T> void _print(stack<T> x){cerr << "[ ";while(!x.empty()){_print(x.top());cerr << " ";x.pop();}cerr << "]";}
template<class T> void _print(deque<T> x){cerr << "[ ";for(T i: x){_print(i);cerr << " ";}cerr << "]";}
template<class T> void _print(vector<T> x){cerr << "[ ";rep(i, 1, x.size()+1){cerr << "(" << i-1 << ")";_print((T)x[i-1]);cerr << " ";}cerr << "]";}

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef pair<int, int> pii;
typedef pair<int, bool> pib;
typedef pair<string, int> psi;
typedef pair<string, string> pss;
typedef vector<pii> vpii;
typedef vector<psi> vpsi;
typedef vector<pss> vpss;

// Vector
template<typename T>            istream& operator>>(istream& is,  vector<T> &v){for (auto& i : v) is >> i;        return is;}
template<typename T>            ostream& operator<<(ostream& os,  vector<T>  v){for (auto& i : v) os << i << ' '; return os;}
// Pair
template<typename T,typename U>          istream& operator>>(istream& is, pair<T, U> &p){is >> p.first >> p.second;        return is;}
template<typename T,typename U>          ostream& operator<<(ostream& os, pair<T, U>  p){os << p.first << ' ' << p.second; return os;}
//Vector + Pair
template<typename T,typename U>          istream& operator>>(istream& is, vector<pair<T,U>> &p){for(auto &i:p){is >> i.fi >> i.se;}return is;}
template<typename T,typename U>          ostream& operator<<(ostream& os, vector<pair<T,U>> &p){for(auto &i:p){os << i.fi << " " << i.se << endl;}return os;}
template <typename T>pair<T, bool> getNthElement(set<T>& searchSet,int index){pair<T, bool> result;if (searchSet.size() > index) {result.first= *(std::next(searchSet.begin(),index));result.second = true;}else result.second = false;return result;}
//Set
template<typename T>            istream& operator>>(istream& is,  set<T> &v){for (auto& i : v) is >> i;        return is;}
template<typename T>            ostream& operator<<(ostream& os,  set<T>  v){for (auto& i : v) os << i << ' '; return os;}

const ll mod = 7+1e9;
const int N = 1+1e6;

// Modulus-Mathematics
template<typename T,typename U>            ll modMul(T a, U b, ll MOD=mod){return ((a%mod)*1LL*(b%mod))%MOD;}
template<typename T,typename U>            ll binpower(T n, U k, ll MOD=mod){T res=1;  while(k){   if(k & 1){res=modMul(res, n, MOD);}  n=modMul(n, n, MOD); k >>= 1;}   return res%MOD;}
template<typename T>              T moduloInverse(T a, ll MOD=mod){return binpower(a, MOD-2);}
template<typename T,typename U>            ll modAdd(T a, U b, ll MOD=mod){return ((a%MOD)+(b%MOD))%MOD;}
template<typename T,typename U>            ll modSub(T a, U b, ll MOD=mod){return ((a%MOD)-(b%MOD)+MOD)%MOD;}
template<typename T,typename U>            ll modDiv(T a, U b, ll MOD=mod){return modMul(a, moduloInverse(b, MOD), MOD);}

void solve(){
    ll n,k,d; cin >> n >> k >> d;
    vll A(n); cin >> A;
    int cnt=0;
    vll pre(n, 0);
    rep(i, 0, n){
        pre[i]=A[i];
        if(i) pre[i]+=pre[i-1];
    }

    int tail=0, head=-1;
    ll ans=-1e18;
    multiset<ll> ms;
    dg(pre)
    while(tail<n){
        while(head+1<n && ((cnt<k && A[head+1]%2) || (cnt<=k && A[head+1]%2==0))){
            head++;
            if(A[head]%2==1)
                cnt++;
            ms.insert(pre[head]);
        }
        dg2(tail, ms)
        ll base = (tail>0?pre[tail-1]:0);
        auto it=ms.upper_bound(base+d);
        if(it!=ms.begin()){
            it--;
            ans=max(ans, *it - base);
        }
        if(tail>head){
            tail++;
            head=tail-1;
        }else{
            if(A[tail]%2==1)
                cnt--;
            ms.erase(ms.find(pre[tail]));
            tail++;
        }
    }
    if(ans==-1e18){
        cout << "IMPOSSIBLE\n";
    }else
        cout << ans << nl;
}

void initialise() {
}

int main() {
    FAST_IO;

#ifndef ONLINE_JUDGE
    freopen("Input.txt", "r", stdin);
    freopen("Output.txt", "w", stdout);
    freopen("Error.txt", "w", stderr);
#endif

//    cout << fixed << setprecision(9);
//    cerr << fixed << setprecision(6);
    srand(time(0));
    int t=1;
    cin >> t;
    initialise();
    rep(i, 1, t+1){
        dg(i)
//        cout << "Case #" << i << ": ";
        solve();
    }

    return 0;
}