Pretesting of Ads and Promotion Offers Can Best Be Achieved

Pretesting of ads and promotion offers can best be achieved by which ONE of the following methods?

A) commissioning at least three focus groups drawn from the target audience
B) commissioning successive individual depth interviews until you have a clear go/no-go answer on each ad or promotion offer
C) designing and using a quantitative ad test or promotion offer test and selecting a large enough sample of the target audience to enable a clear decision
D) using an A/B, or split-run ad test, which can easily be done with a panel sample online
E) designing and using a management judgment ad test