Consider the effect of oil price decrease in Canada on the demand and supply of foreign currency i.e. USD, and the final CAD/USD exchange rates: I. The demand curve shifts down and supply curve shifts down and the exchange rate decreases II. The demand curve shifts up and supply curve shifts down and the exchange rate increases III. The demand curve shifts up and supply curve shifts up and the exchange rate increases IV. The demand curve shifts down and supply curve shifts up and the exchange rate increases Which of the above statement (s) is (are) true? I and II O III and IV IV only III only