SAT English Practice Question

It was a dark and stormy night. The wind howled outside, rattling the windows. Inside, the old mansion was eerily silent. A single candle flickered on the table, casting long shadows across the walls. The only sound was the creaking of the floorboards as I crept down the hallway.

1. A.The sentence contains an unnecessary comma after "sound."
2. B.The sentence requires a comma after "sound" to separate the main clause from the dependent clause.
3. C.The sentence requires a semicolon after "sound" to separate the two independent clauses.
4. D.The sentence contains no punctuation errors.