Barbara is a producer in a monopoly industry. Her demand curve, total revenue curve, marginal revenue curve and total cost curve are given as follows:
Q = 160 - 4P
TR = 40Q - 0.25 img
MR = 40 - 0.5Q
TC = 4Q
MC = 4
How much output will Barbara produce?
a. 0
b. 22
c. 56
d. 72
e. none of the above