Which two reasons justify using CDP?

CDP (Cisco Discovery Protocol) is a proprietary Layer 2 protocol that allows Cisco devices to discover information about directly connected Cisco equipment. "To verify Layer 2 connectivity between two devices when Layer 3 fails" is correct because CDP operates at Layer 2. If Layer 3 (IP) connectivity is down, CDP can still function to confirm that the physical and data link layers are operational between directly connected devices. This helps in troubleshooting by isolating the problem to Layer 3 or above. "To obtain the IP address of a connected device in order to telnet to the device" is correct because CDP advertisements include the IP address(es) of the transmitting device. This allows an administrator to quickly discover the IP address of a directly connected neighbor and then use that address to manage the device remotely via Telnet (or SSH). The other options are incorrect: CDP does not verify cable types; it provides device and interface information. CDP does not determine the status of network services; it focuses on device discovery. While CDP operates on switches, it doesn't provide detailed VLAN information from neighbors beyond basic interface details. CDP does not determine the status of routing protocols; routing protocols themselves handle that.