Which of the following is an example of a compound-complex sentence?

A compound-complex sentence is defined as a sentence that contains at least two independent clauses and at least one dependent clause.

In the given example, the choice that fits this definition is the one where it states, "Although she was tired, she finished her homework, and she went to bed early." This sentence begins with a dependent clause, "Although she was tired," which cannot stand alone as a complete thought. It is followed by two independent clauses, "she finished her homework" and "she went to bed early," both of which can stand alone as separate sentences. This structure combines the complexity of a dependent clause with the coordination of two independent clauses, making it a compound-complex sentence.

The other options lack this specific combination of clauses. One of them is a simple compound sentence, another is a simple sentence, and the last is also a simple sentence. Thus, only the selected option demonstrates the necessary elements of both independent and dependent clauses.