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*/}       }