Answer:
A. price of the good
Explanation:
In any market, the price can be studied in two perspectives. That of the buyer, who uses it as a reference of potential utility, and that of the seller, for the one or which means first a guide of the possible income of his activities and, secondly, the method by which he converts them into profits.
From this point of view there are several concepts that should be kept in mind: price of offer, or price at which the seller offers his merchandise. Demand price is what a consumer is willing to pay. Market price or observed prices are the prices at which real purchases took place.
In a theoretical situation - of free market - the price would be fixed by the law of supply and demand. In the case of a monopoly the price "is on each occasion the highest that can be squeezed out of the buyers, or the one that, presumably, they will consent to give."
In a real situation - imperfectly competitive prices are determined through other mechanisms, such as maximizing marginal income (see also oligopoly; oligopsonio, Monopolistic Competition; Stackelberg competition; cobweb theorem, etc.)