Here are the best options to complete each sentence:

1. The residents **B. reside** in the newly developed suburban area for its tranquility and amenities.
2. The air quality in the city is poor because it is heavily **A. polluting**.
3. He was **A. stuck** in traffic for over two hours due to a major accident on the highway.
4. She **B. relied** on her parents for financial support while attending college.
5. The street market was **C. bustling** with shoppers looking for good deals.
6. The factory was fined for releasing harmful **C. pollutants** into the nearby river.
7. The likelihood of rain tomorrow is quite high, so it is **C. probable** that the event will be postponed.

So, the correct answers are: B, A, A, B, C, C, C.