The correct answer is mopolistic competition.
A monopoly refers to a market situation in which only one producer, or a small group of producers acting in concern, control the supply of some good or service. At the same time new producers are highly restricted. These monopolist producers cpntrol prices ans restrict the output. As you can see all the producers that don't belong to the monopoly have a lot of disadvantages as they have to adjust to the impositions of one.
An example is AT&T in the 80's in telecommunications.
