The correct answer is: A. monopoly
A monopoly is a market structure in which there is only one seller of a good or service. This means that the monopolist has a great deal of market power and can set prices without fear of competition. In the case of a queue of a large number of farmers before a single cold storage in the area, the cold storage is the only seller of cold storage space in the area. This gives the cold storage a great deal of market power and allows it to set prices that are favorable to itself.
The other options are incorrect because they do not describe the market structure in the question. A oligopoly is a market structure in which there are a small number of sellers of a good or service. This means that the oligopolists have some market power, but they are not as powerful as a monopolist. A monopsony is a market structure in which there is only one buyer of a good or service. This means that the monopsonist has a great deal of market power and can set prices without fear of competition. A monopolistic competition is a market structure in which there are a large number of sellers of a good or service, but each seller’s product is slightly different from the others. This means that the sellers have some market power, but they are not as powerful as a monopolist.