For Cisco Catalyst 9176 APs deployed at remote sites without DHCP option 43, automatic WLC discovery can be accomplished using DNS-based CAPWAP controller discovery. By creating a DNS A record named cisco-capwap-controller.<domain> that resolves to the WLC management IP address, APs can query DNS and locate their centralized controller automatically, eliminating the need for site visits or manual configuration. This method is preferred for large-scale or satellite deployments where APs may exist on different subnets and traditional DHCP-based discovery is unavailable. Option A is impractical because manually assigning static IPs to hundreds of APs is operationally complex and error-prone. Option B, using a multicast group, is not supported for cross-subnet controller discovery in CAPWAP; multicast is limited to local subnets. Option D (ap-discovery) is not a recognized standard for WLC discovery; Cisco specifically documents cisco-capwap-controller as the required DNS entry for CAPWAP-based automatic discovery. This approach ensures zero-touch provisioning, simplifies network operations, and guarantees that APs join the correct controller, supporting centralized management and consistent configuration across multiple campuses. Reference topics: Wireless Network Implementation --- CAPWAP discovery, DNS-based controller discovery, Catalyst 9800 WLC onboarding, zero-touch provisioning.