During the Course of a Year, the Velocity of Money

During the course of a year, the velocity of money is tends to be:

A) volatile because it is highly sensitive to changes in the interest rate.
B) constant because the monetary authority strictly controls the money supply.
C) volatile because there are major variations in income and expenditures from month to month.
D) constant because there is little variation in income and expenditures from month to month.