Verifying full system functionality occurs after implementing a fix. This step ensures the solution resolved the issue and that performance is back to expected levels. Comparing current throughput to baseline measurements is part of validation testing to confirm everything is within normal operational parameters.
A). Implement the solution applies the fix but does not confirm results.
C). Document findings happens at the end of troubleshooting.
D). Test the theory comes earlier, when trying to confirm the suspected cause.
References (CompTIA Network+ N10-009):
Domain: Network Troubleshooting - Troubleshooting methodology steps, baselines, verification testing.

Content filtering can be used to block or restrict access to websites and services that facilitate torrenting and other prohibited activities. By implementing content filtering, the company can comply with the ISP's cease- and-desist order and prevent users from accessing torrent sites and engaging in prohibited activities.
References: CompTIA Network+ study materials.

Link Layer Discovery Protocol (LLDP) is a network protocol used for discovering devices and their capabilities on a local area network, primarily at the data link layer (Layer 2). It helps in identifying the connected switch and the specific port to which a device is connected. When troubleshooting a VoIP handset connection, the technician can use LLDP to determine the exact switch and port where the handset is connected. This protocol is widely used in network management to facilitate the discovery of network topology and simplify troubleshooting.
Other options such as IKE (Internet Key Exchange), VLAN (Virtual LAN), and netstat (network statistics) are not suitable for identifying the switch and port information. IKE is used in setting up secure IPsec connections, VLAN is used for segmenting networks, and netstat provides information about active connections and listening ports on a host but not for discovering switch port details.
Reference: CompTIA Network+ Certification Exam Objectives - Network Troubleshooting and Tools section.

After implementing a solution and putting preventive measures in place, the next step is to verify that the system is functioning correctly. This ensures that the issue has been fully resolved.

The longest prefix match is a routing concept used to find the most specific route to a destination IP address.
The routing table performs this calculation to determine the exit interface for a packet, ensuring the most accurate delivery. The document explains:
"Routers use the longest prefix match when searching the routing table to determine the best path for an IP packet. This ensures that the most specific (and thus optimal) route is chosen, based on the destination IP address."