a. In accordance with section three hundred seventeen, a contract may be awarded for a good, service or construction without competition when an agency determines, pursuant to rules promulgated by the procurement policy board, that there is only one source for the required good, service or construction. The agency contract file shall contain the agency's determination that only a single source is available for the required good, service or construction, including the process by which the agency made such determination. Copies of such notice shall be filed with the comptroller.
b. Whenever an agency determines that there is only a single source for a good, service or construction, an agency shall give immediate notice in the City Record of such determination and shall in such notice solicit the application of vendors qualified to provide such good, service or construction, or interested in providing such good service or construction in the future. The procurement policy board shall by rule define the timing and duration of such notification to ensure that vendors qualified to provide such good, service or construction have sufficient opportunity to express their interest to the agency prior to the initiation of any sole source negotiation; provided, however, that if the agency has determined that it should not reveal to the vendor with whom it is negotiating that it is doing so on a sole source basis under circumstances defined by rule of the procurement policy board, the notice required by this subdivision shall be made upon the completion of such negotiations or the award of the contract. Vendors interested in providing such good, service or construction in the future shall be prequalified in accordance with section three hundred twenty-four, or shall be included for receipt of notice in accordance with subdivision a of section three hundred twenty-five.