(a) A pharmacy license expires May 31 of each year.
(b) The board may adopt a system under which pharmacy licenses expire on various dates during the year or every other year, as appropriate.

(c) If the board changes the expiration date of a license, the board shall prorate the license renewal fee to cover the number of months for which the license is valid for the year in which the date is changed. The total license renewal fee is due on the new expiration date.