Question:

A publisher has a text-only leaderboard on top of a page, and a text-only small square ad slot within the content of that page. The small square ad slot has a higher a CTR, but the leaderboard has high CPCs. Is there anything the publisher can do to try and increase their earnings? Select all that apply.

Yes, the publisher should opt in Image ads to both of ad units.
Yes, the publisher should change small square ad unit into large rectangle ad unit.
Yes, the publisher should make sure the medium rectangle ad unit comes first in their HTML code.