This determines where the Universal Currency Converter should get its USD market information from.
This includes any conversions from a cryptocurrency to a fiat such as BTC_USD, ETH_USD and ZEC_USD
Default Value
The default value is "Average Values" which is an average value of all the exchanges listed, weighed based on daily volume. select a different exchange to use only market data from that exchange for crypto to fiat conversions. The utility automatically
updates when there is a price change in the market.