Which three methods can Cisco DNA Center use to discover devices?

Cisco DNA Center uses several methods to discover devices on the network. CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol) are Layer 2 protocols that allow devices to advertise their identity and capabilities to directly connected neighbors, which DNA Center can leverage for discovery. Specifying a range of IP addresses is a direct method where DNA Center actively scans those addresses for devices. While SNMP can be used by DNA Center to gather information from discovered devices, it's not a primary discovery mechanism itself. Ping is used for reachability testing but doesn't provide device identification details for discovery. NETCONF is a protocol for configuring network devices, not for initial device discovery.