Refer to the Following

Multiple Choice

Refer to the following:
The following graph shows the marginal and average product curves for labor, the firm's only variable input. The monthly wage for labor is $2,800. Fixed cost is $160,000.

-When the firm uses 40 units of labor, what is average total cost at this output?

A) $140
B) $40
C) $70
D) $170
E) none of the above