Sure, let's go through each sentence and identify the part that needs correcting:

1. **He feels more happily there than in a crowded and noisy city.**
- **Correction:** "more happily" should be "happier" (A).
- **Explanation:** "Happily" is an adverb, but we need an adjective "happier" to describe the subject "He."

2. **When spring comes, we enjoy to pick flowers on the hill near our house.**
- **Correction:** "to pick" should be "picking" (C).
- **Explanation:** After "enjoy," we use the gerund form of the verb, so it should be "enjoy picking."

3. **The farmers in my region usually don't grow crops and flowers together.**
- **Correction:** No correction needed.
- **Explanation:** The sentence is correct as it is.

4. **It's not always true that living in the city is better than live in the countryside.**
- **Correction:** "live" should be "living" (D).
- **Explanation:** To maintain parallel structure, both verbs should be in the gerund form: "living in the city" and "living in the countryside."

5. **We helped them load the rice onto buffalo-drawn carts and transport them home.**
- **Correction:** "them" should be "it" (D).
- **Explanation:** "Rice" is uncountable, so the correct pronoun is "it."

6. **Will you help me putting up a tent when our school go camping next month?**
- **Correction:** "putting" should be "put" (B).
- **Explanation:** After "help," we use the base form of the verb, so it should be "help me put."

7. **Their village had no running water, so they collected water to the stream.**
- **Correction:** "to" should be "from" (D).
- **Explanation:** They collected water "from" the stream, not "to" the stream.

8. **Kelvin was very kind and he acted more responsible than anyone in the class.**
- **Correction:** "responsible" should be "responsibly" (C).
- **Explanation:** "Acted" requires an adverb to describe how he acted, so it should be "more responsibly."

9. **I lived happily in the farm and there was still more much to explore.**
- **Correction:** "more much" should be "much more" (D).
- **Explanation:** The correct phrase is "much more" to indicate a greater amount.

10. **Which activity do you like most, herding a buffalo or riding a horse?**
- **Correction:** No correction needed.
- **Explanation:** The sentence is correct as it is.