多选题 Given:
2. class Animal { }
3. class Dog extends Animal { }
4. class Cat extends Animal { }
5. public class Mixer＜A extends Animal＞ {
6. public ＜C extends Cat＞ Mixer＜? super Dog＞ useMe(A a, C c) {
7. //Insert Code Here
8. } }
Which, inserted independently at line 7, compile? (Choose all that apply.)

A、 return null;
B、 return new Mixer＜Dog＞();
C、 return new Mixer＜Animal＞();
D、 return new Mixer＜A＞();
E、 return new Mixer＜a＞();
F、 return new Mixer＜c＞();

【正确答案】 A、B、C

【答案解析】