please provide details on how to get to answer. as explicit as possible please

18. "Why has he argued for a stable dollar and a zero inflation? Aren't these inconsistent goals?" These goals are: a) consistent because a stable dollar means zero inflation b) consistent because PPP says that when we have zero inflation our exchange rate will be unchanging c) inconsistent because our exchange rate should fall continuously if our prices don't increase by as much as those of our trading partners d) inconsistent because PPP says that our exchange rate continually changes unless our trading partners have an identical inflation rate