I don't exactly understand the concept needed to solve this problem.

Use the following to answer questions 41-42: S1 So Demand 0 20 40 80 80 100 120 140 160 180 200 use for ch5 Al Refer to the graph above. Assume that the market is initially in equilibrium at a price of $12 and a quantity of 80 units. If the government imposes a $4 per unit tax on this product, it will collect tax revenue in the amount of: $320. (B) $120. _C) $240. D) $640. Refer to the graph above. Assume that the market is initially in equilibrium at a price of