Answer:
Answer to your question is: B) Two players who are unable to communicate with each other.
Explanation:
Prisoner's dilemma is a scenario in which two completely rational individuals/companies might not cooperate, even if it appears that it is in their best interests to do so.
For the Prisoner's dilemma to be true, both persons/companies should not be able to communicate with each other otherwise they will collude and reach mutual best interest.
Other option explanation:
So your option A is totally against the assumption of Prisoner's dilemma.
Option C says Monopolistic competition. In case of Prisoner's dilemma there are 2 equal players and no monopoly so this option is also not correct
Option D says oligopoly with one very large firm. This is also wrong as Oligopoly with one very large firm will have several smaller other players and Prisoner's dilemma work between only 2 players.