Refer to the Following

Refer to the following:
A manger of a firm with market power faces the marginal revenue product and average revenue product curves shown below. The firm incurs weekly fixed costs of $1,800. The firm employs a single variable input, labor, which costs $600 per worker each week.

-The 14^th worker hired adds $_______ to the firm's total revenue each week.

A) $200 per week
B) $400 per week
C) $500 per week
D) $700 per week
E) $900 per week