A Competitive Firm Sells Its Output for $60 Per Unit

A competitive firm sells its output for $60 per unit. Assume that labor is the only input that varies for the firm. The marginal product of the 10th worker is 20 units of output per day; the marginal product of the 11th worker is 16 units of output per day. The firm pays its workers a wage of $150 per day. For the 11th worker, the value of the marginal product of labor is

A) $480.
B) $960.
C) $1,200.
D) $2,400.