Blogs Represent Valuable Sources of Marketing Research Insights, but They

Blogs represent valuable sources of marketing research insights, but they are also a challenge for firms because

A) they include both positive and negative commentary.
B) they are expensive for firms to use.
C) they are affiliated with companies, which biases their comments.
D) they tend to be shy about putting their opinions out in cyberspace.
E) they are unreliable.