The correct answer is C.
OBJ-3.3: Network taps are devices that allow a copy of network traffic to be captured for analysis. They conduct passive network monitoring and visibility without interfering with the network traffic itself. Active monitoring relies on scanning targeted systems, not a network tap. Router-based monitoring would involve looking over the router’s logs and configuration files. SNMP is used to monitor network devices but is considered active monitoring and doesn’t rely on network taps.