多选题 Given:
2. import java.util.*;
3. interface Canine { }
4. class Dog implements Canine { }
5. public class Collie extends Dog {
6. public static void main(String[] args) {
7. List＜Dog＞ d = new ArrayList＜Dog＞();
8. List＜Collie＞ c = new ArrayList＜Collie＞();
9. d. add (new Collie());
10. c. add (new Collie());
11. do1(d); do1(c);
12. do2(d); do2(c);
13. }
14. static void dol (List＜? extends Dog＞ d2) {
15. d2.add(new Collie());
16. System.out.print(d2.size());
17. }
18. static void do2(List＜? extends Canine＞ c2) { }
19. }
Which are true? (Choose all that apply.)