Answer: A complex sentence or a compound-complex sentence.
Explanation: An independent clause is a phrase that has complete meaning by itself, it is the opposite of a dependent (or subordinate) clause which doesn't make complete sense when it is on its own. A complex sentence is formed by a subordinate clause joined to an independent clause. A compound-complex sentence has two independent clauses, joined by one or more subordinate clauses, so the answer can be any of those two.
