Why Are Sites That Attract Heavy Traffic Valuable

Why are sites that attract heavy traffic valuable?

A) A large number of visitors makes it more likely the sponsor will benefit from a higher rate of conversion.
B) The more "eyeballs" the site attracts,the more advertising revenue the site can generate.
C) A large number of visitors makes it more likely the site caters to a niche audience.
D) A & B only.
E) All of these.