Which type of sentence contains a subject and a verb and expresses a complete thought?

The chosen answer, a simple sentence, is indeed correct because a simple sentence is defined as having one independent clause that contains a subject and a verb, and it expresses a complete thought. This straightforward construction is the foundation of sentence structure in English, allowing for clarity and directness in communication.

In contrast, a complex sentence contains at least one independent clause and one dependent clause, making it more elaborate and unable to stand alone as a complete thought without the dependent clause. A compound sentence includes two independent clauses usually joined by a conjunction, which can express two related thoughts but isn't classified as a single complete thought on its own. A compound-complex sentence features multiple independent clauses and at least one dependent clause, further complicating the structure beyond a single complete thought.

Understanding the characteristics of these various sentence types helps in grasping how ideas can be articulated and connected in written and spoken language.