The Big Mac Index Is

The Big Mac index is:

A) An indicator of the economic wealth of a country, applied to a capacity to purchase Big Macs with the average wage.
B) A measure of interest rate parity such that the exchange rates between countries can be compared to assess whether or not interest rates are too high or low in a particular country relative to other major currencies in the world.
C) A measure of purchasing power parity applied to a 'real' product that is essentially identical and available around the world.
D) A measure of interest rate parity such that the exchange rates between countries can be compared to assess whether or not interest rates are too high or low in a particular country relative to other major currencies in the world and a measure of purchasing power parity applied to a 'real' product that is essentially identical and available around the world.
E) None of the given answers.