问题如下：
The manager of a small manufacturing firm gathers the following information about the firm’s labor utilization and production:
Refer to the data in Exhibit 2. The marginal product of labor demonstrates increasing returns for the firm if the number of workers is closest to but not more than:
选项：
A.2.
B.3.
C.4.
解释：
B is correct.
Marginal product is equal to the change in total product divided by the change in labor. The increase in MP from 2 to 3 workers is 190: MP = ΔTP/ΔL = (510 – 320)/(3 – 2) = 190/1 = 190.
考点：边际收益
分析：本题考点比较常规，边际收益=总收益的增加量/产量的增加量
那么可以算的第三个产量时的边际收益（第二个产量增加到第三个产量时收益的增加量）是最大的，即，MP = ΔTP/ΔL = (510 – 320)/(3 – 2) = 190/1 = 190.
想问一下，所有题目中的return是 marginal product 的意思嘛？
