What is the approximate wavelength of an 802.11ac radio wave?

You told your customer that multipath fading may be mitigated simply by moving one or both of the receivers antennas a small amount, usually by one to four wavelengths away from its original position. Your customer is prepared to make the change, but does not know the wavelength for 802.11ac.

What is the approximate wavelength of an 802.11ac radio wave?
A . 5.5 cm (2.16 inches)
B . 12 cm (4.72 inches)
C . 15.24 cm (6 inches)
D . 45 cm (17.71 inches)

Answer: A