Answer:
The correct answer is C.
Step-by-step explanation:
A Complex sentence is a sentence having both an independent clause and one dependent clause. As the name connotes, an independent clause is capable of standing on its own in a sentence. While a dependent clause as it contains both subject and verb cannot stand on its own.
Examples of complex sentences are; John was delighted he was part of the football match, Michael laughed when I joke, I cooked it myself etc.
To easily identify complex sentences, two clauses are closely connected with a subordinating conjunction.