In General,people Behave More Competitively (In a Self-Interested Fashion)in Social

In general,people behave more competitively (in a self-interested fashion) in social dilemmas when compared to prisoner's dilemmas.Which of the following statements,if true,will weaken this argument?

A) Social dilemmas provide anonymity.
B) In the case of social dilemma, it is easy to alter and reinforce behaviors of others.
C) Social dilemmas are riskier than prisoner's dilemmas.
D) In the case of a social dilemma the costs of defection are spread out, rather than concentrated upon one person.