With Identical Firms, Constant Input Prices, and All the Other

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 a change in equilibrium quantity but not price.
D) a shift in demand has no effect on the long-run average cost, resulting in a change in equilibrium price but not quantity.