What will happen to the equilibrium price and quantity for complement goods (oil, windshield wiper fluid, etc.) at convenience stores that sell gasoline, but not diesel fuel, in the downtown district on Monday, Tuesday, Wednesday, and Thursday?

a. The equilibrium price will go down, and the equilibrium quantity will go up.

b. The equilibrium price will go up, and the equilibrium quantity will go down.

c. Both the equilibrium price and quantity will go down.

d. Both the equilibrium price and quantity will go up.