Which of the following is not an example of user authentication?

Which of the following is NOT a key component of a social network?

A) Most profile pages include some form of blog, discussion forum, or chat room so that friends can communicate with the person profiled. B) For most social networks, the user's profile page serves as the "home base" for most activities. C) Many social networks include various means of user-to-user communication, including private email and one-to-one instant messaging. D) Social networks constantly use new technology or means of communication to stay competitive.

In the formula =B2*B3 is located in cell C3, which cell is the dependent cell?

A) B3 B) B2 C) C1 D) C3