Timmy's Trophies Operates in a Perfectly Competitive Market

Multiple Choice

Timmy's Trophies operates in a perfectly competitive market.If trophies sell for $20 each and average total cost per trophy is $15 at the profit-maximizing output level,then in the long run

A) more firms will enter the market.
B) some firms will exit from the market.
C) the equilibrium price per trophy will rise.
D) average total costs will fall.