When testing the IFE (International Fisher Effect), we run a linear regression: y=alpha + beta *x, where I) y is a given foreign exchange rate II) y is the change of a given foreign exchange rate III) x is the change of two interest rates (r_h - r_f) IV) x is (1+r_h)/(1+r_f)-1

a) I) and III)

b) I) and IV)

c) II) and IV) d) II) and III)

e) None of the above