Talk- Radio Station KOOK Is at Approximately 90 Megahertz on the Radio

Talk- radio station KOOK is at approximately 90 megahertz on the radio dial. This means that KOOK broadcasts

A) an electromagnetic wave whose frequency is 90 × 10⁶ vibrations/second.
B) an electromagnetic wave whose wavelength is 90 × 10⁶ vibrations per second.
C) a sound wave whose frequency is 90 × 10⁶ vibrations/second.
D) a sound wave whose frequency is 90 vibrations/second.
E) an electromagnetic wave whose frequency is 90 vibrations/second.