An individual or family qualifies as a person of eligible income: for projects that are State or federally funded, if the individual or family meets the income requirements of the State or federal program involved; or for other projects, if the individual or family, by a determination under subsection (b) of this section, lacks sufficient income or assets without financial assistance to purchase or rent decent, safe, and sanitary housing without overcrowding. The chief elected official or the chief elected official’s designee, who may be the executive director of an authority or the board of commissioners of the authority, shall determine whether an individual or family qualifies as a person of eligible income under subsection (a)(2) of this section. Determination of qualifying income levels may vary for the elderly, individuals with disabilities, other persons with special needs, particular projects or programs, or particular parts of the political subdivision.