Which of the following techniques does a vulnerability scanner use in order to detect a vulnerability on a target service?

Port scanning is a reconnaissance step used to discover open ports and running services, not a technique for detecting specific vulnerabilities on those services.

Banner grabbing is an information-gathering technique that identifies service version strings to inform target selection, but it is not the mechanism by which a vulnerability is confirmed.

Injecting arbitrary data is associated with fuzzing or active exploitation during penetration testing, not with the standard passive or credentialed checks performed by vulnerability scanners.

Analyzing service responses is the core mechanism vulnerability scanners use to identify weaknesses - the scanner sends crafted requests and compares the replies to known vulnerability signatures or expected behavior baselines. This response analysis can reveal version-specific flaws, misconfigurations, and exposed attack surfaces without requiring manual exploitation. The quality and depth of response analysis directly determines what vulnerabilities the scanner can detect.