The correct option is
D oligopoly
Meaning of Oligopoly:
Oligopoly refers to a market situation or a type of market organisational in which a few firms control the supply of a commodity. The competing firms are few in number but each one is large enough so as to be able to control the total industry output and a moderate. However, increase of its output or sales will reduce the sales of rival firms by a noticeable amount.
This is surely the case if three to six or even ten firms control an industry’s output, with each controlling enough to exert influence on price. Oligopoly is the most prevalent form of market organisation in the manu¬facturing sector at modern times and arises due to various reasons (such as, economies of scale, patents and trademarks, control over the sources of raw materials, government’s sanction, need of a large capital, and so on). The chief characteristic of oligopoly is the interdependence among the rival sellers.
Types of Oligopoly:
Oligopoly is of two types:
(a) Pure oligopoly
Here, the oligopolists sell practically homogeneous products. This type is found in steel, copper, cement petrol and a few other industries.
(b) Differential Oligopoly:
In such a case a few firms sell similar but not identical products under the same conditions. It is found in automobiles, tyres, electrical appliances, cigarettes, baby food and a few other industries.