(a) It may rent or lease the dwelling accommodations therein only to persons of low income and at rentals within the financial reach of such persons of low income;
(b) It may rent or lease to a tenant dwelling accommodations consisting of the number of rooms (but no greater number) which it deems necessary to provide safe and sanitary accommodations to the proposed occupants thereof, without overcrowding;
(c) The dwellings in low-rent housing as defined in this article shall be available solely for families whose net annual income at the time of admission, less an exemption of one hundred dollars ($100.00) for each minor member of the family other than the head of the family and his spouse, does not exceed five (5) times the annual rental (including the value or cost to them of water, electricity, gas, other heating and cooking fuels, and other utilities) of the dwellings to be furnished such families. For the purpose of determining eligibility for continued occupancy, a public housing agency shall allow, from the net income of any family, an exemption for each minor member of the family (other than the head of the family and his spouse) of either (a) one hundred dollars ($100.00), or (b) all or any part of the annual income of such minor. For the purpose of this subparagraph, a minor shall mean a person less than twenty-one (21) years of age.