In which of the following statements is the variable s defined as a generic type?

a) String s = “This is a string”;

b) Object s = new String(“This is a string”);
c)  class B {}
    class A<T extends B> {
      T s;
      T getS() {
        return s;
      }
    }
d) class T {}
   class R extends T {}
                
   T s = new R();