Answer: C) Marginal revenue will fall and marginal cost will rise.
Step-by-step explanation:
The profit-maximizing equilibrium is the production point where the Marginal Revenue equals the Marginal cost.
As the monopolist moves towards this point, they will see their marginal costs increase because they will be producing more goods.
For a monopolist to sell more goods however, they will need to reduce their prices. This means that Marginal revenue will come down.
Marginal revenue will keep decreasing and Marginal cost will keep increasing until both of them become equal to each other.