Which three demonstrate an “is a” relationship？（） 

• A、 public class X {  }     public class Y extends X { }
• B、 public interface Shape { }     public interface Rectangle extends Shape{ }
• C、 public interface Color { }     public class Shape { private Color color； }
• D、 public interface Species { }     public class Animal { private Species species； }
• E、 public class Person { }    public class Employee {      public Employee（Person person） { }
• F、 interface Component { }     class Container implements Component {   private Component[] children； }