Final answer:
The frequency of a wave traveling at 60 cm/second with a wavelength of 15 cm is calculated by dividing the wave speed by the wavelength, resulting in a frequency of 4 Hz. So the correct option is D.
Step-by-step explanation:
If a wave is traveling at 60 cm/second and has a wavelength of 15 cm, the frequency can be calculated using the formula f = v / λ, where f is the frequency, v is the velocity of the wave, and λ (lambda) is the wavelength. To find the frequency, we divide the velocity by the wavelength:
f = 60 cm/s / 15 cm = 4 Hz.
Therefore, the correct answer is D. 4 Hz.