The CSRS or FERS basic annuity of an employee or survivor who has elected retirement coverage under subpart D of this part is reduced in the following order—

1. (a) For age, if applicable, as provided under sections 8339(h) and 8415(f) of title 5, United States Code.
2. (b) For noncontributory service performed before October 1, 1982, if applicable, as provided under 5 U.S.C.A. 8339(i), note.
3. (c) For deficiency, as determined under subpart F of this part.
4. (d) To provide a survivor annuity to a spouse or former spouse, if applicable, as provided under sections 8339(j)(4) and 8419(a) of title 5, United States Code.
5. (e) Any other reductions which may apply.