An engineer is planning an image upgrade of the WLC, and hundreds of APs are spread across remote sites with limited WAN bandwidth. The engineer must minimize t...

An engineer is planning an image upgrade of the WLC, and hundreds of APs are spread across remote sites with limited WAN bandwidth. The engineer must minimize the WAN utilization for this upgrade.
Which approach must be used for the AP image upgrade?

A. Predownload the new code to the APs. B. Use the Smart AP image upgrade feature. C. Allow the APs to download their code after WLC reboot. D. Execute parallel TFTP code upgrade on the APs via SSH.