Correct Option: C

Duopoly means a market in which two producers of the same good are predominantly powerful. In some theries, the term is used specifically to denote the existence of only two suppliers of a good. Competition refers to a condition in a market in which firms are attempting to increase their profits at the expense of their rivals. Oligopoly refers to a market that is dominatted by a few firms producing differentiated products. Monopoly refers to a market in which there is only one supplier and no other firms are able to enter. According to the Fair Trading Act, 1973, Monopoly is defined as any firm (or group of firms acting together) that accounts for 25 percent or more of the market output of a good or service.