Which One of These Must Be True If Absolute Purchasing

Which one of these must be true if absolute purchasing power parity is to absolutely hold?

A) Customer preferences for an item must be identical across markets.
B) There must be greater demand for the item in one area as compared to another area.
C) Forward rates must equal spot rates.
D) The goods traded must have a feature unique to each individual market.
E) Transaction costs must be imposed on both ends of a trade.