Sentence:  At the most general level, policymakers in open economies face a macroeconomic <WSD>"trilemma</WSD>": 1. to stabilize the exchange rate; 2. to enjoy free international capital mobility; 3. to engage in a monetary policy oriented toward domestic goals. Because only two out of the three objectives can be mutually consistent, policymakers must decide which one to give up. 
Meaning of the word marked with <WSD> tags:  A circumstance in which a choice must be made between three options that seem equally undesirable or, put another way, in which a choice must be made among three desirable options, only two of which are possible at the same time.