明度指色彩的深浅和明暗程度，主要是受光线强弱的影响。

A．The equilibrium price would increase, but the impact on the amount sold in the market would be ambiguous.
B．The equilibrium price would decrease, but the impact on the amount sold in the market would be ambiguous.
C．Both equilibrium price and equilibrium quantity would increase.
D．Equilibrium quantity would increase, but the impact on equilibrium price would be ambiguous.