When the prisoners' dilemma game is generalized to describe situations other than those that literally involve two prisoners, we see that cooperation between the players of the game a. always works to the detriment of society as a whole. b. can be difficult to maintain, but only when cooperation would make at least one of the players of the game worse off. c. can be difficult to maintain, even when cooperation would make both players of the game better off. d. always works to the benefit of society as a whole.