Wavelength = (speed) / (frequency)
so in order to answer this question, we need the speed of sound.
Without using my precious time to go look it up, I'm guessing that
the speed of sound at STP is roughly 343 m/s .
If that estimate is accurate, then
Wavelength = (343 m/s) / (440 /s) = 0.78 meter .
Choice-#2 is much closer to this result than any of the others,
so choice-2 must be it.
Actually, we can 'reverse engineer' Choice-#2 and find the number
it uses for the speed of sound.
Speed = (wavelength) x (frequency)
= (0.75 m) x (440 /s) = 330 m/s .
The author of the question used 330 m/s for the speed of sound.
