Answer:
C. f = 440 Hz
Step-by-step explanation:
- In any wave, there is a fixed relationship between the wavelength (distance between two sucesive crests), the frequency (number of cycles per unit time) and the perturbation speed, as follows:

where v = speed of the wave
λ = wavelength
f = frequency
- Replacing by the givens in (1) and solving for f, we have:
