对于类A,B,C,D和接口 IA,IB,IC 有以下的定义, class A{ } class B extends A implements IA{ } class C extends B implements IB{ } class D extends B implements IC{ } interface IA{ } interface IB extends IA{ } interface IC extends IA{ } A tmpA = new A( ) B tmpB = new B( ) C tmpC = new C( ) D tmpD = new D( ) 下列类型转换中,正确的是( )