Final answer:
Adding a dependent clause to a simple sentence creates a complex sentence, which includes one independent clause and one or more dependent clauses. The correct answer is option A.
Step-by-step explanation:
When you add a dependent clause to a simple sentence, the result is a complex sentence. A complex sentence is composed of one independent clause (a clause that contains a subject and a predicate and can stand alone as a sentence) and at least one dependent clause (also known as a subordinate clause). The dependent clause begins with words such as although, because, if, and since, and it cannot stand alone as a full sentence. In contrast, a compound sentence contains two or more independent clauses joined by a coordinating conjunction like for, and, nor, but, or, yet, or so (fanboys).