能给解释解释为什么选CD吗（java）1.classSuper{2.privateinta;3.protectedSuper(inta){this.a=a;}4.}...11.classSubextendsSuper{12.publicSub(inta){super(a);}13.publicSub(){this.a=5;}14.}Whichtwo,independently,willall

Question

能给解释解释为什么选CD吗（java）
1. class Super{
2. private int a;
3. protected Super(int a){this.a = a;}
4. }
...
11. class Sub extends Super{
12. public Sub(int a){super(a);}
13. public Sub(){this.a = 5;}
14. }
Which two, independently, will allow Sub to compile? (Choose two.)
A. Change line 2 to:
public int a;
B. Change line 2 to:
protected int a;
C. Change line 13 to:
public Sub(){this(5);}
D. Change line 13 to:
public Sub(){super(5);}
E. Change line 13 to:
public Sub(){super(a);}

Answer 1

C. Change line 13 to:
public Sub(){this(5);} // 执行的是12行，this(5)找的是Sub类的对应构造方法
D. Change line 13 to:
public Sub(){super(5);} //执行的是3行，super(5)找的是父类对应的构造方法