Answer: Option (b) is correct.
Step-by-step explanation:
In a monopolistic competitive market condition, there are many firms who are selling the product which are similar in nature but products are not perfect substitute. So, these firms are producing differentiated products.
The Profit-maximizing level of output for monopolistic firm is at a point where marginal revenue is equal to marginal cost and the corresponding point on the demand represents the profit maximizing price.