Unremarried spouses of deceased volunteer firefighters or volunteer ambulance workers.

Such exemption may be continued to such deceased enrolled member's unremarried spouse; provided, however, that:A. Such unremarried spouse is certified by the authority having jurisdiction for the incorporated volunteer fire company, fire department or incorporated voluntary ambulance service as an unremarried spouse of a deceased enrolled member of such incorporated volunteer fire company, fire department or incorporated voluntary ambulance service; andB. Such deceased volunteer has been an enrolled member for at least 20 years; andC. Such deceased volunteer and unremarried spouse had been receiving the exemption prior to the death of such volunteer.