Long-run equilibrium in a monopolistically competitive industry requires the representative firm to earn zero economic profits, because
the lack of barriers to entry means entry will drive the profit-maximizing level of output to a point where Price =
Average total cost
Marginal revenue > Average total cost at the profit-maximizing level of output
the lack of barriers to entry means entry will drive the profit-maximizing level of output to a point where Price =
Marginal cost
the government regulates the price