48. Potential real GDP is expected to grow at 4% in 1999 and 2000. The income velocity of circulation of money is expected to remain stable at 7 over this two-year period. Which of the monetary policies will keep inflation at zero? a. A 7 percent annual growth in the MI money stock. b. A 4 percent annual growth in the MI money stock. c. A 3 percent annual growth in the MI money stock. d. A zero percent annual growth in the MI money stock