Answer: A) Compound
Explanation:
A compound sentence is formed by joining two independent clauses connected by a coordinating conjunction - for, and, nor, but, or, yet, so.
"Ashley wants peperoni pizza, but her friend Toni is a vegetarian" is constituted of two independent clauses. The clauses are related, and they were joined by the coordinating conjunction "but". Thus, we have a compound sentence.
Further information:
A simple sentence is constituted of a single independent clause. It has a subject and a predicate, and it expresses a complete thought.
A complex sentence is formed by joining an independent clause and a dependent one. A dependent clause needs the independent one to give it context, so that it makes sense. It does not express a complete thought on its own.
A compound-complex sentence is formed by two independent clauses and a dependent one, at least.
