Use the Following to Answer Questions

Use the following to answer questions:
Figure: Game-Day Shirts
-(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) firms will enter the industry.
B) firms will exit the industry.
C) the industry is in equilibrium.
D) the industry has minimized average total cost.