Answer:
Set ATC cost to minimum?
Explanation:
Not sure what the question is but in general, you want to produce where MR=MC as that is the profit maximizing point.
If this a perfectly competitve market and firm, where MR=MC is at the Min. ATC, so the market is productively efficient. It is also allocatively efficient because in a Perfectly Competitive market because you are also producing where P=MC. So at that point, ATC are at a minimum.