The correct option is B Both (A) and (C)
In an Oligopoly market structure, there are barriers to the entry of new firms into the market. This is because there is a tough competition among the existing firms. This causes these few firms to have control over the resources, capital and also as they have been in the market for a long time, they get economies of scale. All this causes the market to be unattractive to new firms and becomes a barrier to entry.