Although Internet Advertising Is Growing at a Very Rapid Pace

Multiple Choice

Although internet advertising is growing at a very rapid pace, many advertisers are skeptical about its potential as a global promotion tool because of (the) :

A) potential annoyance factor of ads.
B) potential difficulty of audience measurement.
C) difficulty to measure branding campaigns.
D) uncertainty as to which metrics to use to measure success
E) all of the above.