The correct revision is..
"You're being dramatic," said Eliza.
"I don't think it's dramatic to say that you're going to fail the humanities class if you don't pass its final exam," replied her mother.
You're is short for you are. It's is short for it is. You use its for possession.
Answer:
b. Kentucky, Georgia, and Tennessee; these were in which we earned the most money.
Explanation:
Use a semicolon between independent clauses joined by a coordinating conjunction if the clauses are already punctuated with commas or if the clauses are lengthy