Optional prisoner's dilemma

The optional prisoner's dilemma is a game that two people can play. In this game, each person has two choices - to cooperate or to defect. If both people choose to cooperate, then both get a reward. But if one person chooses to cooperate and the other person chooses to defect, then the person who chose to defect will get a bigger reward than the person who chose to cooperate. If both people choose to defect, then both get a small reward. So, the challenge of the game is to decide which choice to make that will give you the biggest reward.