Actually, the correct answer is "C". Both waves will travel at the same rate of speed, which is 343 meters per second, irregardless of the frequency. The frequency, expressed in hertz, is the number of waves passing a given point in one second. The one that has 629 Hz has 629 waves passing per second. These waves would have to be shorter in wavelength than the other one, which was 529 Hz. The 529 Hz wave has longer wavelengths than does the 629 Hz wave. So it is a matter of how long the wave is, rather than which one moves faster. Both waves progress through air at the same rate of speed. All waves in the electromagnetic spectrum travel at the same rate of speed, but they all vary according to wavelength. The correct order of the waves in the electromagnetic spectrum is radio waves, the longest, followed by microwaves, infrared waves, visible light, ultraviolet waves, xrays, and gamma waves, the shortest.