58.

Given these 4 classes:

      class Test<T1> where T1 : new()
      {
            public static string getName<T2>() where T2 : T1
            {
                  return "OK";
            }
      }

      abstract class A
      {
            protected A() { }
            public int a;
            public int b;
      }

      class B : A
      {
            public B() { }
            public int c;
            public int d;
      }

      class C : B
      {
            public int d;
            
            public static void Main()
            {
              //What is the correct statement
            }            
      }

Which of the following calls will return "OK"

According to the Test class, T1 must be non abstract and contain a public constructor with no parameters. The "where T1 : new()" constraint ensures this.

In the declaration of getName, T2 is given the constraint that it must inherit T1 "where T2 : T1".

A is abstract so it's can't be T1.
C can't be T1 because there must be a class that inherits T1 to use T2. 

The only combination that works is Console.WriteLine(Test<B>.getName<C>());