Calculate the monopolist's profit under the following conditions. The intersection of the marginal revenue and marginal cost curves occurs where output is 10 units. At an output of 10 units, the monopoly price is $20 per unit, the marginal cost is $12 per unit, and the average variable cost is $4 per unit, and average fixed cost is $8 per unit.
a. $120
b. $100
c. $80
d. $60