Allen is a marketing manager who received a series of ads from his creative team. He wants to use A/B testing to find the ads in the series that yield the best results. Which type of ads will Allen compare?

Ads used in identical ways, on the same channels, and directed at the same audience.
Ads with exposed groups, on the same message, and directed at the same audience.
Ads with unexposed groups, on the same budget, and directed at the same audience.
Ads with unexposed groups, on the same channels, and directed at the same audience.