Distinguish between the short run and the long run. In the short run, ______. In the long run, ______.
A. a firm's plant is fixed; a firm can change its plant
B. the quantity of only one factor of production is fixed; the quantities of all factors of production can be varied
C. all factors of production are variable except technology; the quantities of all factors of production can be varied
D. all costs are sunk costs; the quantity of only one factor of production is fixed