4. Which of the following would cause the real exchange rate between pesos and U.S. dollars (in terms of pesos per dollar) to decrease?

a. an increase in net capital flows from Mexico to the United States

b. an increase in the real interest rate in Mexico relative to the United States

c. a doubling of prices in both Mexico and the United States

d. a decrease in oil exports from Mexico to the United States

e. an increase in the balance of payments on the current account in the United States