Question #N66

The sentence "When I first moved to a new city, I felt like a fish out of water, but I quickly adapted to my new surroundings." is grammatically correct. However, the sentence "When I first moved to a new city, I felt like a fish out of water, but I quickly adapted to my new surroundings, and I was very happy." is grammatically incorrect. Which change to the second sentence would make it grammatically correct?

Which of the following changes to the second sentence would make it grammatically correct?
A. Change "and" to a semicolon.
B. Remove "and" from the sentence.
C. Change "and" to a comma.
D. Change "and" to a period.