In the Short-Run Equilibrium in a Monopolistically Competitive Industry, a Firm's

Multiple Choice

In the short-run equilibrium in a monopolistically competitive industry, a firm's marginal cost is equal to its _________ but in the long run equilibrium, a firm's average cost is equal to its __________.

A) price; demand.
B) average cost; price.
C) marginal revenue; marginal cost.
D) marginal revenue; price.