A divorced spouse's inclusion in the computation of the overall minimum rate ends the earlier of:

1. (a) The month before the month in which the divorced spouse dies; or
2. (b) The month before the month the employee dies; or
3. (c) The month before the month in which the divorced spouse remarries; or
4. (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.