已知类和接口定义如下, 正确的类定义是? abstract class A1{ int a;} abstract class A2{ int b;} interface IA{ } interface IB{ }
A.
class C1 implements A1 implements IA{ }
B.
class C2 extends A1 ,extends A2 { }
C.
class C3 extends A1,A2 implements IA,IB{ }
D.
class C4 extends A1 implements IA,IB{ }