Which component in a musical note is referred to as the pitch of a sound?
a. wavelength
c. time
b. frequency
d. distance?

Option B) frequency (and also option a; wavelength)

Explanation: The waves can be described by the basic equation of:

Velocity = frequency*wavelength.

As we know, all the soundwaves have (almost) the same speed, so for each frequency, there is one associated wavelength corresponding to a soundwave.

Now, the quantity usually associated to the pitch of the sound is the frequency, where high frequencies coincide with the high pitch, and lower frequencies coincide with the lower pitch, so the "correct" option is b) frequency.

None the less, the pitch of the sound also can be described by the wavelength, as I already discussed before.