Use the Following to Answer Question

Use the following to answer question:
Figure 8.5
-(Figure 8.5) The graph shows a firm's marginal cost curve. This firm operates in a perfectly competitive industry with market demand and supply curves given by Q^d = 100 - 8P and Q^S = -20 + 2P, where Q is measured in millions of units. Based on the figure, how many units of output will the firm produce at the equilibrium price?

A) 1,100
B) 800
C) 1,200
D) 400