Which of the Following Statements Holds True for Wikis

Which of the following statements holds true for Wikis?

A) Their key use is to anonymously share ideas in an unattributed manner.
B) Their key use is creating an effective form for online advertising, customer tracking, and service personalization.
C) Their key use is to discover and reinforce affiliations, identify experts, message individuals or groups, and virally share media.
D) Their key use is to poll a diverse crowd and aggregate opinions to form a forecast of an eventual outcome.
E) Their key use is to collaborate on common tasks or to create a common knowledge base.