Why this is right?

A monopoly is a state where one firm produces all of the input in a given market. As a small firm owner, I can easily enter the market as a monopolist if there is a focus on controlling the market only for certain goods or services. Although there is a possibility of nice profit charging 10% less than the monopolist, I should consider the following possibilities before going ahead and challenging the monopolist:

• I should know the monopolist can change the price of the goods or services or its rules.
• It is possible that the monopolist can create more problems for a single organization by affecting its name and quality.
• The monopolist can advertise their products, build more goodwill, and earn consumers' trust, affecting my firm.
• The monopolist can reduce its prices below my firm's average total cost, which will affect my firm as it cannot reduce its expenses below its average total cost as it leads to losses.

The monopolist charges what the market is willing to pay and hence determines the price for it. The monopoly could achieve the profit-maximizing output level by increasing quantity by a small amount, calculating marginal revenue and marginal cost. Then either increasing output as long as marginal income exceeds marginal cost or reducing output if the marginal cost exceeds marginal revenue.