The correct answer is A. Compound.
A simple sentence consists of subject/s + verb/s + predicate. It is one complete thought. Ex: We took a chance.
A compound sentence has more than one complete sentence, known as independent clause. They are joined by coordinating conjunction such as <em>but, and, for, or</em>, etc. Ex: We took a chance, and we were sorry.
A complex sentence consists of at least one independent clause and one or more dependent clauses. The dependent clauses are joined to the independent clause by subordinating conjunctions like <em>because, since, if, before</em>, etc. Ex: We took a chance because we needed the results.
In this case, "because we needed it" has no meaning on its own since it is a dependent clause.
