In connection with this demonstration, the Secretary of Housing and Urban Development may enter into contracts with public housing agencies to provide not more than 1,500 incremental vouchers and certificates under sections
1437f
(b) and
1437f
(o) of this title. A public housing agency may not require that a frail elderly person live in a particular structure or unit, but the agency may restrict the program under this section to a geographic area, where necessary to ensure that the provision of supportive services is feasible. At the end of the demonstration period, the public housing agency shall give each frail elderly person the option to continue to receive assistance under the housing certificate or voucher program of the agency. In the demonstration, the Secretary may also provide for supportive services in connection with existing contracts for housing assistance under sections
1437f
(b) and
1437f
(o) of this title.