Final answer:
A complex-compound sentence requires at least one independent clause and one dependent clause, typically joined by a semicolon, coordinating conjunction, or both. Therefore, the correct answer is a) independent clause.
Step-by-step explanation:
A complex-compound sentence, also known as a compound-complex sentence, requires at least one independent clause and one dependent clause.
An independent clause is a group of words that can stand alone as a sentence, while a dependent clause cannot stand alone. To form a complex-compound sentence, you can join independent clauses using a semicolon, where the second clause restates or closely relates to the first.
Additionally, a coordinating conjunction can be used to connect two independent clauses. A common method to remember coordinating conjunctions is by the mnemonic FANBOYS: for, and, nor, but, or, yet, so.
Understanding the correct use of commas, semicolons, and coordinating conjunctions is essential to correctly punctuating complex-compound sentences.