"uncle's" & "uncles'"

[xxwzs]

Some senior high school exercise:

1. In summer, I always call at my ______, which are in the same town. But my ______ is in another city, so I can’t go there.
A. uncle’s…aunt’s B. uncle’s…aunts’ C. uncles’…aunt’s D. uncles’…aunts’

2. When do you go to the shops to bring me ______?
A. a tin of fruit B. a fruits tin C. a fruit tin D. a tin of fruits

3. After several day’s hardworking, we have made ______ on the design.
A. much improvement B. many improvement C. several improvements D. some improvement

4. ______ is only surpassed by that of ______.
A. The dog's intelligence...monkeys and apes B. The intelligence of dogs…monkeys and apes
C. The dogs' intelligence...monkeys and apes D. The intelligence of dogs’…monkeys’ and apes’

Could you please tell me which is/are the correct answer(s) to each question? It is very helpful that you could give some explanations.
I think there might be multiple answers to each question or very similar answers, which I can't distinguish from among.

 

[bhaisahab]

Which ones would you choose?

 

[xxwzs]

Which ones would you choose?

First, thank you for your reply. Here are my choices:
1. C (according to the forms of BE in the sentences: The speaker has more than one uncle and just one aunt.)
2. A&C (I don't know how to explain)
3. A&C (Improvement functions as not only an uncountable noun but a countable one, so I think A and C both work.)
4. A&B (something similar to question 2, but I also have no idea how to make an explanation)
I just made such choices based on the grammar taught in my country.
Could you please give me the right answer(s)?