In long-run equilibrium, both purely competitive and monopolistically competitive firms will

A) produce at minimum average total cost.
B) earn economic profits.
C) achieve allocative efficiency.
D) equate marginal cost and marginal revenue.

Long-Run Equilibrium

A state in economics where all firms and consumers have fully adjusted to all changes in the market, resulting in the optimal distribution of resources in the long term.

Purely Competitive

A market structure characterized by a large number of small firms, a homogeneous product, perfect knowledge, and free entry and exit, resulting in firms being price takers.

Allocative Efficiency

The optimal distribution of resources in an economy, ensuring that each good or service is produced up to the point where the last unit provides a benefit equal to the cost of producing it.