Which two classes use the Shape class correctly?

A. public class Circle implements Shape 
   {
    private int radius;
   }
B. public abstract class Circle extends Shape 
   {
    private int radius;
   }
C. public class Circle extends Shape 
   {
   private int radius;
   public void draw();
   }
D. public abstract class Circle implements Shape 
   {
    private int radius;
    public void draw();
   }
E. public class Circle extends Shape 
   {
    private int radius;
    public void draw()
    {
     /* code here */
    }
   }
F. public abstract class Circle implements Shape 
   {
     private int radius;
     public void draw() 
     { 
      /* code here */ 
     }
   }