Why Can Interactions in an International Monetary Regime Be Like

Why can interactions in an international monetary regime be like a Prisoner's Dilemma?

A) Each government has an incentive to cheat by pegging its currency; the result is a world where every government wants to peg its currency to someone else.
B) Each government has an incentive to cheat by devaluing its currency,and the result is that all governments become worse off because of competitive devaluations.
C) Each government faces a choice between fixing its currency's exchange rate and letting the currency float freely.
D) All governments have a clear incentive to create an international government to regulate monetary affairs even though this will make them captive to its rules.