Answer:
B. participles
Explanation:
Participles are words created from verbs, that are used as an adjective. For example, the word winning is a verb. But in this sentence, "The winning competitor wins the trophy." the word winning is used to describe someone and not necessarily just the action they have participated in.
Past perfect is the answer
Consider the following conditional sentences, and pay close attention to the conditional verbs in each of them:
If my cousin had been just a little taller, he could have been a basketball player.
If I had enough money, I would travel around the world.
If Alex finishes his essay, he will come over tomorrow.
After looking at how a conditional verb is used in a sentence. I would say that Conditional is the correct answer.