单选题 In the short run, an increase in output (marginal product) at low levels of production will most likely cause:

A、 an increase in the marginal cost clue to the rising total 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.

【正确答案】 C

【答案解析】[解析] 如图所示，在短期内，如果产量处于较低水平，则生产专门化趋势的增强有助于提高产出(MP)。需要注意的是，如果产量处于较高水平，则收益递减规律将最终使边际成本上升，进而使产出水平(MP)降低。