child
(3) “child” means any natural, illegitimate, adopted, or posthumous child or stepchild of a deceased or permanently and totally disabled public safety officer who, at the time of the public safety officer’s fatal or catastrophic injury, is— (A) 18 years of age or under; (B) over 18 years of age and a student as defined in section 8101 of title 5 ; or (C) over 18 years of age and incapable of self-support because of physical or mental disability;