Answer:
The correct answer is option d.
Explanation:
For a competitive industry, there is no price effect on revenue. The firm is a price taker. When the firm changes it quantity sold, it faces the output effect on revenue.
A monopolist firm, on the other hand, faces both output effect and price effect on the revenue. Since a monopoly firm is a price maker and faces a downward sloping curve. It needs to reduce the price to increase output. To increase the marginal revenue it needs to increase output.