Answer:
C is halved
Explanation:
The frequency and the wavelength of a wave are related by the equation:

where
v is the speed of the wave
f is the frequency
is the wavelength
From the equation above, we see that for a given wave, if the wave is travelling in the same medium (and so, its speed is not changing), then the frequency and the wavelength are inversely proportional to each other.
Therefore, if the frequency doubles, the wavelength will halve in order to keep the speed constant:

Answer:
It would be hard to test scientifically since it's subjective and can only be proven true if you conducted some experimentations and observations.
the answer is foot luv <3