A divorced spouse's inclusion in the computation of the overall minimum rate ends the earlier of:
(a) The month before the month in which the divorced spouse dies; or
(b) The month before the month the employee dies; or
(c) The month before the month in which the divorced spouse remarries; or
(d) The month before the month in which the divorced spouse becomes entitled to a retirement or disability benefit under the Social Security Act based upon a primary insurance amount which is equal to or exceeds the divorced spouse annuity before reduction for age.