In What Sense Can a Reserve Requirement Be Said to Be

In what sense can a reserve requirement be said to be a tax on bank intermediation?

A) Banks must pay tax on any funds deposited in a reserve account at a rate equal to the applicable corporate income tax rate.
B) Banks must pay tax on any funds removed from a reserve account at a rate equal to the applicable corporate income tax rate.
C) Banks must pay taxes on the amount by which they fail to meet their reserve requirements.
D) Banks are unable to lend out all their deposits.