单选题 Assume that output increased from 1550 to 1850 units per day as a result of increasing labor from 200 to 210 workers. The marginal product of labor is closest to:

A、

A. 1.55 units per day per worker.
B、

B. 30 units per day per worker.
C、

C. 1.25 units per day per worker.

【正确答案】 B

【答案解析】Marginal product is the additional output per additional unit of an input (labor). Since output changed by 300 units and labor changed by 10 workers, the marginal product is 300/10=30 units per day per worker.