While implementing a non-carrier-grade wireless backhaul, a technician notices the current channel selection is extremely polluted with various RF signals. Upon...

While implementing a non-carrier-grade wireless backhaul, a technician notices the current channel selection is extremely polluted with various RF signals. Upon performing a spectral analysis, the technician discovers a channel containing almost no RF pollution. Unfortunately, the technician is unable to select that channel.
Which of the following is the MOST likely reason for this issue?

A. The channel is reserved for licensed band use. B. The channel selection is defective; contact the manufacturer. C. The channel must be unlocked by the vendor. D. The device requires a firmware update to unlock the channel.