A profit-maximizing, monopolistically competitive restaurant serves 60 burgers a day at a total cost of $180 and earns a total profit of $180. In the long run, everything else equal, the

a.restaurant will charge more than $6 per burger.
b.restaurant's average total cost will rise and its total revenue will fall.
c.restaurant will sell more burgers at a lower average profit per burger.
d.All of the above are correct.