The QTOM assumes two components to be stable over time. Which two?

Page $3$:

a$)$ real GDP and price level

$18$

$19$

$20$

b$)$ the velocity of money and the price level

$22,23$

c$)$ the money supply and the velocity of money

$25$

$26$

d$)$ real GDP and the velocity of money

$28$

$29$