The demand and supply of coffee are shown here, with an equilibrium price of $4 per pound and an equilibrium quantity of 4,000 pounds per week. Suppose the government imposes a $3 tax per pound of coffee, collected from the buyer. Draw a new curve (demand or supply), accurately positioned, that reflects the impact of this tax.

a) Demand curve shifts left
b) Demand curve shifts right
c) Supply curve shifts left
d) Supply curve shifts right