单选题
Suppose that rubber is the primary input in the production of golf balls. If the price of rubber increases while all else remains constant, then in the short-run: A. the marginal and average variable cost curves shift upward, but not the average total or average fixed cost curves. B. the average total and average variable cost curves shift upward, but the marginal and average fixed cost curves will shift downward. C. the marginal, average variable, and average total cost curves will shift upward, but the average fixed cost curve will not shift.
【正确答案】
C
【答案解析】Marginal cost (MC) is the change in total cost resulting from the production of one additional unit. In the short run, MC will typically decline if output is increased, reaching a minimum, and then will increase sharply as maximum production capacity is approached. Total variable costs are those costs that rise as output increases. For a given level of output, the average variable cost (AVC) is the total variable cost divided by output. In the short run, AVC will slightly decline, to a certain point at which output will increase by smaller and smaller amounts, causing AVC to rise. This is the point of diminishing returns, where it will take successively larger amounts of the variable factor to expand output by one unit.
Total fixed cost is the sum of costs that do not vary with output. Average fixed cost (AFC) is the total fixed cost divided by output. AFC will be high for low rates of output, but will decline as output increases, causing the curve to slope downward to the right. Average total cost (ATC) is the total cost divided by the total number of units produced. ATC will be a U-shaped curve, since AFC will be high for small rates of output and MC will be high as the plant approached maximum capacity.