The Following Figure Shows Equilibrium at the Industry and Firm

The following figure shows equilibrium at the industry and firm level. Figure 9.6
In the figure,
S₁,S₂,S₃ are the market supply curves.
D₁ and D₂ are the market demand curves.
MC is the marginal cost curve of the firm.
MR₁ and MR₂ are the marginal revenue curves of the firm.
ATC is the average-total-cost curve of the firm.
-According to Figure 9.6,at a price of $1,the firm would earn an economic profit of:

A) $15.
B) $9.
C) $13.50.
D) $12.50.
E) 0.