Explanation/Reference:
Incorrect Answers:
C: Multiple records in different transaction currencies can be aggregated, compared, or analyzed with regard to a single currency, by using an exchange rate. This is known as the base currency. You first define a base currency for the organization and then define exchange rates to associate the base currency with transaction currencies. The base currency is the currency in which other currencies are quoted. The exchange rate is the value of a transaction currency equal to one base currency.
References: https://msdn.microsoft.com/en-us/library/gg328355.aspx
https://debajmecrm.com/2014/07/15/understanding-currency-field-in-microsoft-dynamics-crm/