What is a prisoners' dilemma?
a. a game in which prisoners are stumped because they cannot communicate with each other
b. a game that involves no dominant strategies
c. a game in which players collude to outfox authorities
d. a game in which players act in rational, selfminusinterested ways that leave everyone worse off

D. a game in which players act in rational, selfminusinterested ways that leave everyone worse off

Explanation:

The prisoners dilemma involves the idea that both people would act in self interests, but this self interests would not help the other one or the group to have a better outcome, so people is acting in detriment of the society or the other participant, it often happens that both people chose to protect themselves damaging the other person, and thus since both had choosen that option both are worse off after it.

i would say b. research typically uses a variety of sources