18. A constant-cost, perfectly competitive widget industry is in long-run equilibrium. A decrease in the
price of gadgets, a substitute for widgets, will most likely result in
A. an increase in the demand for widgets, followed by a decrease in the supply of widgets
B. higher short-run and long-run prices for widgets
C. short-run losses for widget producers, followed by the exit of some firms
D. an upward shift in all short-run cost curves, followed by a higher long-run price for widgets
E. a higher short-run price for widgets, followed by an increase in the quantity produced