Which of the Following Explains Why Purchasing Power Parity Does

Which of the following explains why purchasing power parity does not completely explain long-run fluctuations in exchange rates?

A) Some goods and services produced in any country are not traded internationally.
B) Consumer preferences for goods and services across countries are very similar.
C) Most countries do not impose barriers to trade.
D) Most countries have free markets with little, if any, government regulation.
E) The prices of most internationally traded commodity are set in U.S.dollars.