A single-plant firm trying to select the rate of output consistent with an overall plant size that yields the minimum efficient scale will choose a rate of output for which

C) long-run average total cost is lowest at that rate of output.

Explanation:

The firm will achieve its highest efficiency at the point where average total cost intersects with marginal cost. Profits will also maximize at this point since the product's price should equal marginal cost. Average total cost will also be lowest at this point. In this attached graph this point is given at (Q,P).  

no, a company likes to look at potential employees that are professional, well mannered, clean, honest, etc. don't show up looking/acting like a clown. (unless that's your job xd) hope this ! =^-^=