One Reason That Real Exchange Rates Do NOT Equal ________ $\bar { a }$

One reason that real exchange rates do NOT equal ________ is because ________.

A) zero; of perfect arbitrage among traded goods
B) one; of the inclusion of nontraded goods in price levels
C) zero; real interest rates are not equal across countries
D) $\bar { a }$ ; the output gap is never zero
E) the nominal exchange rate; of equalization of prices across countries