Java |构造函数|问题3

关于Java的构造函数，以下哪项是正确的?

1) Constructor name should be same as class name.
2) If you don't define a constructor for a class, 
    a default parameterless constructor is automatically
    created by the compiler. 
3) The default constructor calls super() and initializes all 
   instance variables to default value like 0, null.
4) If we want to parent class constructor, it must be called in 
   first line of constructor.

(A) 1
(B) 1、2
(C) 1、2和3
(D) 1、2、3和4答案： (D)
解释：
这个问题的测验