class A {  }  class Alpha {  private A myA = new A（）；  void dolt（ A a ） {  a = null；  }  void tryIt（） {  dolt（ myA ）；  }  }  Which two statements are correct？（）  

• A、 There are no instanced of A that will become eligible for garbage collection.
• B、 Explicitly setting myA to null marks that instance to be eligible for garbage collection.
• C、 Any call on tryIt（） causes the private instance of A to be marked for garbage collection.
• D、 Private instances of A become eligible for garbage collection when instances of Alpha become eligible for garbage collection.