单项选择题

A. public class Session implements Runnable, Clonable{   public void run ();public Object clone () ; }
B. public class Session extends Runnable, Cloneable {  public void run() {/*dosomething*/}       public Object clone() {/*make a copy*/} }
C. public abstract class Session implements Runnable, Clonable {       public void run() {/*do something*/}       public Object clone() {/*make a copy*/}        }
D. public class Session implements Runnable, implements Clonable {       public void run() {/*do something*/}       public Object clone() {/*make a copy*/}       }