Which of the following statements about exchange rates istrue?A. Exchange rates

Which of the following statements about exchange rates istrue?A. Exchange rates were fixed prior to establishing a floating-rateinternational currency system and all countries set a specificparity rate for their currency relative either to the Canadian orto the U.S. dollar.B. Day-to-day fluctuations in exchange rates currently are causedby changes in parity rates.C. A floating-rate international currency system has been operatingsince 1973.D. All of the choices.