Which of the following statements is true about velocity?

Select one:

a.In the short run, velocity varies but in the long run, velocity is relatively constant.

b.In the short run, velocity is relatively constant but in the long run, velocity varies.

c.Velocity is relatively constant in the short run and in the long run.

d.Velocity fluctuates with fluctuations in economic activity and changes in the growth rate of money supply.