Read the following sentence. Then, answer the question. Beatrice was unable to concentrate on her project because her brother’s stereo was turned up to full volume.

Which statement is correct?

A comma is needed in this sentence before the word "because" to separate the dependent clause from the independent clause.
The phrase "on her project" should be separated from the rest of the sentence by commas on both sides.
The dependent clause follows the independent clause in this sentence, so no comma is needed.
This is a compound sentence made up of two independent clauses, so no comma is needed