Which of the following statements is true?
Select one:
a. The speculative demand for money at possible interest rates gives the demand for money curve its upward slope.
b. There is an inverse relationship between the quantity of money demanded and the interest rate.
c. According to the quantity theory of money, any change in the money supply will have no effect on the price level.
d. The transactions demand for money is used as an insurance agent against unexpected needs.