(a) If a municipality, county, or other political subdivision of the State makes appointments to government positions under a civil service or merit system law or ordinance, the unit that provides eligibility lists for appointments shall adopt rules or regulations to grant special credit to honorably discharged veterans of the armed forces of the United States who have been residents of the State for at least 5 years immediately preceding the date on which the veteran takes a merit system examination.

(b) (1) The unit may determine the nature and extent of the special credit granted to veterans.

(2) The unit may grant a greater credit to veterans with a disability than to veterans who do not have a disability.

(c) The credit granted to a veteran under this section may be extended to:

(1) the spouse of a veteran if the veteran is unable to qualify for merit system appointment because of a disability; and

(2) the unmarried surviving spouse of a deceased veteran.

(d) The unit may exempt war veterans under the age of 55 years from any age limitation or requirement.