还是不太能理解？

问题如下：

In the short run, an increase in output at low levels of production will most likely cause:

选项：

A.an increase in the marginal cost due to the rising total fixed cost. B.an increase in the marginal cost due to the law of diminishing returns. C.a decrease in the marginal cost due to economies from greater specialization.

解释：

The marginal cost decreases at low levels of output due to economies from greater specialization. However, at higher levels of production, it eventually increases because of the law of diminishing returns.

中文解析：

由于专业化程度的提高，边际成本在低产出水平下下降。然而，在较高的生产水平上，由于收益递减规律，它最终会增加。