单选题 The short-run supply curve for a firm under perfect competition: A. is its average variable cost curve. B. is its average variable cost curve above marginal revenue. C. is its marginal cost curve above average variable cost.

【正确答案】 C

【答案解析】The supply curve for a firm under perfect competition is its marginal cost curve above average variable cost. As long as price exceeds AVC, the firm will produce up to the quantity where MC =Price, which is also MR in this case.