Answer: "B) Difficult entry, C) Mutual interdependence, D) Market control by a few large firms" are other characteristics of this market structure.
Explanation: An oligopoly is a market structure where there are few relevant competitors and each of them has some capacity to influence market variables (such as price and amount of balance).
The Oligopoly characteristics are:
Small group of producers.
Producers can influence the price and market quantity.
They are strategically interdependent speaking.
There are usually barriers to entry for new producers.
The product offered can be interchangeably homogeneous or differentiated.