The correct answer is C. Raquel was tired; so she decided to go home.
Explanation:
According to grammar rules, the semicolon is used to separate independent clauses without including conjunctions. Also, the semicolon is correct if the sentences are joined by a conjunctive adverb (however, instead, moreover, as a result, etc.)
This implies it is not correct to use a semicolon with a regular conjunction (and, but, or, so); therefore, the sentence "Raquel was tired; so she decided to go home" has an error in semicolon usage because there is a semicolon along with a conjunction. Instead, a comma should be used or the conjunction "so" should be omitted.
