What essay and what video are you referring to?
You are correct with the answer you already selected.
Answer:
Why people accept social influence. There are a number of reasons why people allow social influences to affect their thoughts and behavior. One reason is that we often conform to the norms of a group to gain acceptance of its members. ... Additionally, group conformity enables a sense of cohesion within a society.
Your answer is B."Of."
Your preposition is a noun or pronoun expressing relations to another word or phrase in the sentence.
