What Is a Major Challenge That Marketers Face When Entering

What is a major challenge that marketers face when entering social networks?

A) Advertising rates are highly negotiable. Marketers can easily spend too much.
B) Marketers have to blend in. Just showing up in a social network is suspect.
C) Marketers cannot tell who is a connector and who is an audience member.
D) People on social networks tend to be greedy. They want free products from marketers.
E) Marketers are used to using traditional media. They do not know how to navigate social sites.