All of the following are major sources of user$-$generated content problems except:

A$.$ Mutinous movements are an extension of bad reviews.

B$.$ Research indicates that customers are not sophisticated enough to know that few, if any, products are perfect.

C$.$ Crackpots may also use the network or UGC site as a way of expressing passionately held views about unrelated topics, such as UFOs, government cover$-$ups, fantastic conspiracy theories, and so forth.

D$.$ Most customers want to know the disadvantages of a product before purchasing it so they can determine if those disadvantages are important for their application.

E$.$ Unfavorable reviews are another risk.

F$.$ When a business participates in a social network or opens its site to user$-$generated content $($UGC$),$ it opens itself to misguided people who post junk unrelated to the site's purpose.