All of the following requirements must be met in order that an employee may be exempt under section 13(b) (9):
(a) The employee must be ``employed as'' an announcer, or a news editor, or a chief engineer.
(b) The employee must be employed ``by'' a radio or television station.
(c) The major studio of such radio or television station must be located in a city or town which meets the prescribed population and locality tests.