What Is a Floating Exchange Rate

What is a floating exchange rate?

A) A monetary system in which the exchange rates of major currencies retain nearly the same value with respect to the U.S.dollar but are allowed to fluctuate during crises.
B) A monetary system in which the exchange rates of currencies are set at a permanent price of gold.
C) A monetary system in which the exchange rates of major currencies retain nearly the same value with respect to gold but are periodically adjusted during currency crises.
D) A monetary system in which exchange rates are allowed to change according to their market prices.
E) A trading system in which governments do not limit how many goods can be sent between countries.