Governing boards of school districts may release temporary employees requiring certification qualifications under the following circumstances:
(a) At the pleasure of the board prior to serving during one school year at least 75 percent of the number of days the regular schools of the district are maintained.
(b) After serving during one school year the number of days set forth in subdivision (a), if the employee is notified before the end of the school year of the district’s decision not to reelect the employee for the next succeeding year.