Answer:
A. Competitive markets face perfectly elastic demand and marginal revenue, while monopolies face downward-sloping demand and marginal revenue.
Step-by-step explanation:
In the case when competitive firms and monopolies generated at the level in which the marginal cost is equivalent to marginal revenue keeping the other things constant so the price should be less in the competitive market as compared to the monopoly because in the competitive markets it face perfectly elastic demand but in the monopoly it face the down ward sloping demand curve
Therefore the option a is correct