Ответ:

А

1. bird's

2. her

3. my

4. our

5. Bob's

6. their

7. my

8. Bart and Lisa's

B

1. Whose cards are these?- They're ours.
2. Whose cap is this?- It's mine.
3. Whose DVDs are these?- They're theirs.
4. Whose fish is this?- It's Bill's.
5. Whose gloves are these?- They're yours.
6. Whose flowers are these?- They're hers.

C

1. my
2. your, mine
3. their, ours
4. your, hers
5. My
6. their
7. your, our
8. my, hers
9. It's
10. my, ours
11. their
12. our