The correct answer is: C. to compete successful with the rival firms
A firm under monopolistic competition advertises to create a brand identity and differentiate itself from its rivals. This can help the firm to attract more customers and charge a higher price.
Option A is incorrect because advertising does not usually lower the cost of production. In fact, advertising can be quite expensive.
Option B is incorrect because advertising does not always lead to increased sales and profits. In some cases, advertising can actually lead
to lower sales and profits if it is not done effectively.Option D is incorrect because a firm under monopolistic competition can raise the price, but it will not be able to raise the price as much as a firm under monopoly. This is because there are other firms in the market that offer similar products, so customers have more choices.