以下的类(接口)定义中正确的是( )

A. public class A{ private int x; public getX(){ return x; }}
B. public abstract class A{ private int x; public abstract int getX(); public int aMethod(){ return 0; }}
C. public class A{ private int x; public abstract int getX();}
D. public interface interfaceA{ private int x; public int getX(){ return x; }}