public class SomeException {  } Class a：  public class a {  public void doSomething（） { }  } Class b：  public class b extends a {  public void doSomething（） throws SomeException { }  }  Which is true about the two classes？（） 

• A、 Compilation of both classes will fail.
• B、 Compilation of both classes will succeed.
• C、 Compilation of class a will fail. Compilation of class b will succeed.
• D、 Compilation of class a will fail. Compilation of class a will succeed.