Exam 1z0-809 topic 1 question 4 discussion

Given:
1. abstract class Shape {
2. Shape ( ) { System.out.println ("Shape"); }
3. protected void area ( ) { System.out.println ("Shape"); }
4. }
5.
6. class Square extends Shape {
7. int side;
8. Square int side {
9. /* insert code here */
10. this.side = side;
11. }
12. public void area ( ) { System.out.println ("Square"); }
13. }
14. class Rectangle extends Square {
15. int len, br;
16. Rectangle (int x, int y) {
17. /* insert code here */
18. len = x, br = y;
19. }
20. void area ( ) { System.out.println ("Rectangle"); }
21. }
Which two modifications enable the code to compile?
abstract