The correct answer is D. Oligopoly
Explanation:
In economics and related areas, an oligopoly occurs if only a few companies dominate the production or supply of a specific product or service. This differs from a monopoly because in this there is only one company or firm domination. Moreover, in oligopolies as in monopolies competition is imperfect because small firms or new firms cannot compete.
In the case presented, the competitive structure is an oligopoly because three big important firms dominate telecommunication, and therefore this service is controlled by a few companies. Also, due to this, the competition is not fair or perfect because even when the three companies use non-price competition, small companies cannot compete with the three firms.
