Answer:
The only mistake i see is that when you wrote it is public transport i think you should have wrote it is a public transport.
Explanation:
Researchers are someone who searches about someone and learns about someone's daily lives or talents.
Answer: C. Going to the beach in the summer is one of my favorite vacations and so is going to the mountains in the fall.
The sentence presented above is corrected by omitting the "comma" after the conjunction "and" making it a grammatically correct sentence.