What of these is the best definition of a market economy?

A market economy is where the pricing of goods in the market is based only on private individuals or companies. Government has very little say in it.

Currently, as of february 2016, an american traveling in france would be by the exchange rate. the weakness of the euro and the strength of the us dollar means that items in france cost less to an american than they otherwise would. of course, if this trend reverses and the us dollar weakens and the euro strengthens, such as was happening in early 2008, an american traveling in france would have an adverse experience because items would cost relatively more.

Ibelieve the answer is benjamin franklin.