Use the Following to Answer Question

Multiple Choice

Use the following to answer question:
-(Figure: Game-Day Shirts) Use Figure: Game-Day Shirts.Rick is one of 10 vendors who sell game-day T-shirts at football games in a perfectly competitive market.His costs are identical to the costs of the other 9 vendors.If the price of a shirt is $9,in the long run:

A) new firms will enter the industry.
B) existing firms will exit the industry.
C) the industry is in equilibrium.
D) the industry has minimized average total cost.