What is the Achilles' heel of monetary rules? A. Disparities between IMF standards and US Treasury department standards. B. They are unable to cope with extraordinary macroeconomic events. C. That it amplifies the "excess financial elasticity" of domestic policy regimes, ie it exacerbates their inability to prevent the build-up of financial imbalances, or outsize financial cycles, that lead to serious financial crises and macroeconomic dislocations. D. The international gold standard falling