Assume your typical customer has the demand function q = 20 - p and your marginal cost is MC = 10 dollars, as illustrated in the graph. Then, the optimal block pricing strategy is
a) block size = 10 units and price per block = 50 dollars
b) block size = 10 units and price per block = 150 dollars
c) block size = 5 units and price per block = 75 dollars
d) block size = 5 units and price per block = 125 dollars