With Identical Firms,constant Input Prices,and All the Other Characteristics of a Competitive

With identical firms,constant input prices,and all the other characteristics of a competitive market

A) a shift in demand has no effect on the long-run average cost and so there is no change in equilibrium price and quantity.
B) a shift in demand will change the equilibrium price and quantity.
C) a shift in demand has no effect on the long-run average cost, resulting in change in equilibrium quantity but not price.
D) a shift in demand has no effect on the long-run average cost, resulting in change in equilibrium price but not quantity.