The fundamental aim of a monopolist is to

Option A is incorrect because a monopolist does not necessarily want to charge a very high price. In fact, if they charge a price that is too high, they may not be able to sell all of their output. Option B is incorrect because a monopolist does not necessarily want to sell all of what they have produced. In fact, if they produce too much output, they may not be able to charge a high enough price to earn maximum profits. Option D is incorrect because a monopolist does not necessarily want to ensure that costs are a declining function of output. In fact, if costs are declining, the monopolist may not be able to earn maximum profits.