The answer is C because I already took the test! Good luck:)
Answer: People who assail competition (b.) attack competition.
Explanation:<u> </u><u>The word "assail" is a verb and it makes reference to the act of attacking something or critizing it strongly</u>. Therefore, "assail" is a transitive verb and<u> two of its synonyms are "attack" and "assault"</u>. Taking this into account, "people who assail competition" means "people who attack competition". In this sentence, "assail" is part of a relative clause which has been introduced by "who".
Be interested in what the person is talking about, maintain good eye contact, and actually pay attention to what the person is saying.