【单选题】
class ClassA { <br /> public int numberOfinstances； <br /> protected ClassA（int numberOfinstances） { <br /> this.numberOflnstances = numberOfinstances； <br /> } <br /> } <br /> public class ExtendedA extends ClassA { <br /> private ExtendedA（int numberOfinstances） { <br /> super（numberOflnstances）； <br /> } <br /> public static void main（String[] args） { <br /> ExtendedA ext = new ExtendedA（420）； <br /> System.out.print（ext.numberOflnstances）； <br /> } <br /> } <br /> Which is true？（） 
A、 420 is the output.
B、 An exception is thrown at runtime.
C、 All constructors must be declared public.
D、 Constructors CANNOT use the private modifier.
E、 Constructors CANNOT use the protected modifier.
查看正确答案
