Untitled

namespace Test
{
    class Program
    {
        public static void Main(string[] args)
        {
            var Maria = new Data();
            Maria.Name = "Maria";
            var student = new Student();
            student.data.Add(Maria);    //warning CS8602: Dereference of a possibly null reference.

            System.Console.WriteLine(Maria.Name);
        }

    }


    class Student
    {
        public List<Data>? data { get; set; }
    }

    class Data
    {
        public string? Name { get; set; }
    }
}