下面的接口(类)定义正确的是:( )

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; }}