(a) An application for service may be made by any interested person, including, but not being limited to, the United States, any State, county, municipality, or common carrier, and any authorized agent of the foregoing.

(b) Where service is offered: Any product may be inspected, wherever an inspection program employee is available and the facilities and the conditions are satisfactory for the conduct of the service.

(c) The applicant must have a tax identification number for billing purposes.