In a Perfectly Competitive Market, a Decrease in Market Demand

In a perfectly competitive market, a decrease in market demand in a long-run constant-cost industry causes:

A) an increase in price, quantity, and profit in the short run.
B) an increase in price, quantity, and profit in the long run.
C) a decrease in price, a decrease in quantity, and a decrease in profit in the short run.
D) a decrease in price, a decrease in quantity, and a decrease in profit in the long run.