Group M, the World's Largest Advertising Buyer, Requires Which of the Following

Multiple Choice

Group M, the world's largest advertising buyer, requires which of the following in order for an ad to be considered viewable?

A) 50% of the pixels must be in view for at least one second.
B) 50% of the pixels must be in view for at least two seconds.
C) 100% of the pixels must be in view for at least one second
D) 100% of the pixels must be in view for at least two seconds