~Aloha!~
In my opinion, I think the answer might be B)
It's really the only logically one when I started researching about it. I hope I helped! <3
Answer:
Social force
Explanation:
Social factors are an important influence on consumer behavior. Social forces refer to groups of people impacting in other groups behavior and desiring to buy some particular kind of items.
In this particular example, the book Fifty Shades of Grey had a huge success especially among women, so this gender group had an influence among other women and the ones who hadn't read the book did it and then it would be a frenzy for female-targeted romances packaged for the mainstream reader.
This would be an example of how a group (social force) impacts the marketing environment.
B, advocate. Being an advocate means you speak out for it, or that you show your support for something.
