Answer:
When marginal cost meet with the demand curve
Explanation:
The industry will do the most efficient allocation of resources when the marignal cost met the demand curve.
When that occur the cost of producing an additional unit matches the amount the consumers are willing to pay for it thus, are in equilibrium.
The government will also have to look for the marginal revenue at this point to determinate wheter or not to subsidize the monopoly or not to avoid going bankruptcy
