Which of the following tools provides a visual diagram of a network?

Network Mapper applications discover hosts and services across a network and render their relationships as a visual diagram or map, giving administrators a clear picture of network topology. This discovery and visualization function is the defining purpose of network mapping tools, distinguishing them from diagnostic or monitoring utilities.

A network analyzer (packet sniffer or protocol analyzer) captures and decodes network traffic at the packet level to diagnose issues, but it does not produce visual network topology diagrams.

A Time Domain Reflectometer sends electrical pulses down a cable and measures signal reflections to locate cable faults or breaks - it is a cable-testing instrument, not a network diagramming tool.

System Monitor tracks operating system performance counters such as CPU, memory, and disk utilization, and does not map or diagram network devices or topology.