An oligopoly is a market for a good or service that (5 points)

has few competitive firms
is perfectly competitive
has one buyer
has one seller

The correct option is the first one; An oligopoly is a market for a good or service that has few competitive firms.

An oligopoly is a market form or industry dominated by a small number of large sellers known as oligopolists. Oligopolies generally result in a reduction of competition and thus higher prices for consumers.

the best description of postwar writers might be progressive.

following the war, writers showed a tendency to work on artistic or social matters rather than political themes. while postwar literature may not have been the greatest period of english literature, the themes provided excellent critics a high number of novels. such examples include anthony burgess, anthony powell and frank kermode, all of which can be placed under the progressive view.