For a perfectly competitive $($PC$)$ firm to maximize profit they must first find the quantity where

Group of answer choices

marginal revenue $($MR$)=$ marginal cost $($MC$)$

marginal revenue $($MR$)=$ average total cost $($ATC$)$

marginal revenue $($MR$)=$ average variable cost $($AVC$)$

marginal revenue $($MR$)=$ average fixed cost $($AFC$)$