import java.util.*；  public class WrappedString {  private String s；  public WrappedString（String s） { this.s = s； }  public static void main（String[] args） {  HashSet hs = new HashSet（）；  WrappedString ws1 = new WrappedString（”aardvark”）；  WrappedString ws2 = new WrappedString（”aardvark”）；  String s1 = new String（”aardvark”）；  String s2 = new String（”aardvark”）；  hs.add（ws1）； hs.add（ws2）； hs.add（s1）； hs.add（s2）；  System.out.println（hs.size（））； } }  What is the result？（） 

A.  0

B.  1

C.  2

D.  3

E.  4

F.  Compilation fails.

G.  An exception is thrown at runtime.