(b) Any denial of a request for a record will be written and signed by the Administrative Officer or other employee, including a statement of the reason for denial. That statement will contain, as applicable:

1. (1) A reference to the specific exemption under the Freedom of Information Act authorizing the withholding of a record, and to the extent consistent with the purpose of the exemption, an explanation of how the exemption applies to the record withheld.
2. (2) If a record requested does not exist, or has been legally disposed of, the requester will be so notified.

(c) In unusual circumstances, the time limit prescribed in paragraph (a) of this section may be extended by written notice to the person making the request setting forth the reasons for the extension and the date on which a determination is expected to be dispatched. No extension notice will specify a date that would result in an extension for more than twenty working days. As used in this paragraph, “unusual circumstances” means, but only to the extent reasonably necessary to the proper processing of the particular request—

1. (1) The need to search for and collect the requested records from other establishments that are separate from the office processing the request;
2. (2) The need to search for, collect, and appropriately examine a voluminous amount of separate and distinct records which are demanded in a single request; or
3. (3) The need for consultation, which will be conducted with all practicable speed, with another agency having a substantial interest in the determination of the request or among two or more components of the agency having substantial subject-matter interest therein.