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 caused bychanges in parity rates. C.A floating-rate international currency system has been operatingsince 1973. D.All of the choices.