Which of the following would a security administrator implement in order to discover comprehensive security threats on a network?

Design reviews evaluate the security architecture of a system during the planning or development phase and are not used for active discovery of threats on a live network.

Baseline reporting documents the normal operating state of a system and is used to detect deviations over time, but it does not actively probe for or identify security vulnerabilities.

A vulnerability scanner (such as Nessus or OpenVAS) systematically tests network devices, operating systems, and applications against a database of known vulnerabilities, providing comprehensive visibility into exploitable weaknesses across the entire network. It is the primary tool a security administrator uses for proactive, broad threat discovery.

Code review is a manual or automated analysis of application source code for programming flaws and is not applicable to discovering network-wide security threats on production infrastructure.