In What Way Can an Oligopolistic Market Structure Be Beneficial

In what way can an oligopolistic market structure be beneficial to society?

A) Oligopolistic firms compete through advertising,which increases economic efficiency.
B) Oligopolistic firms are able to exploit all existing economies of scale and operate at the minimum of long-run average costs,and thereby reduce the use of society's resources.
C) An oligopolistic market structure is most conducive to non-competitive behaviour which leads to lower prices for consumers in the long run.
D) An oligopolistic market structure is most adaptive to today's rapid rate of technological change.
E) Oligopolistic firms compete through innovation,which is a driving force of economic growth and increasing living standards.