Refer to the Graphs Shown, Which Depict a Perfectly Competitive

Refer to the graphs shown, which depict a perfectly competitive market and firm in a constant-cost industry. If market demand increases from D₀ to D₁, in the long run:

A) new firms will enter this market and price will return to P₀.
B) new firms will enter this market and price will remain at P₁.
C) some firms will exit this market and price will return to P₀.
D) some firms will exit this market and price will remain at P₁.