Answer:
D. at zero profit, her revenue will cover all her costs, both explicit and implicit (opportunity cost).
Step-by-step explanation:
We should understand that there are accounting profit and economic profit.
Accounting profit will represent the revenues and expenxes of the activity.
while economic profit will add the opportunity cost (earnings from other alternatives to the factors) So at an ecnomic profit of zero the producer is in the best possible spot as none other activity will provide better yield.