Suppose a Competitive Market Has a Horizontal Long-Run Supply Curve

Multiple Choice

Suppose a competitive market has a horizontal long-run supply curve and is in long-run equilibrium. If demand decreases, we can be certain that in the short-run,

A) at least some firms will shut down.
B) price will fall below marginal cost for some firms.
C) price will fall below average total cost for some firms.
D) at least some firms will enter the industry.