The Cisco Aironet 2800 Series APs feature a dual-radio architecture with a dedicated 5 GHz radio (slot 1) and a Flexible Radio Assignment (XOR) radio (slot 0) that can operate in either 2.4 GHz or 5 GHz, or be assigned to monitor mode for scanning functions. Since all existing SSIDs and services are 5 GHz only, the slot 1 (dedicated 5 GHz) radio is responsible for all current client connectivity — it must remain in Client Serving mode to maintain uninterrupted 5 GHz WLAN service. The XOR radio (slot 0), currently either idle or operating as a secondary 5 GHz radio, can be repurposed without impacting client service. Setting the XOR radio to Monitor mode enables it to continuously scan all channels across both the 2.4 GHz and 5 GHz spectrum for rogue AP detection, using the embedded CleanAir and WIDS capabilities. In Monitor mode, the XOR radio operates full-time as a dedicated scanner, providing rogue detection coverage on 2.4 GHz (previously uncovered since all services were 5 GHz) and supplementary scanning on 5 GHz. This eliminates the need for additional dedicated monitor mode APs. Options A, C, and D either place the slot 1 radio in a non-client-serving role (disrupting existing connectivity) or use the inappropriate Sniffer mode instead of Monitor mode for rogue detection. Reference: WLSD Study Guide — Cisco 2800 XOR Radio Architecture, Monitor Mode for Rogue Detection, Flexible Radio Assignment, WIDS Design.