正解:A
Retrospective detection is a feature of Cisco Advanced Malware Protection (AMP) for Endpoints that performs correlation of telemetry, files, and intrusion events that are flagged as possible active breaches.
Retrospective detection allows AMP to continuously analyze file activity across the network and identify malicious behavior that was previously undetected. Retrospective detection can also trigger alerts and remediation actions when a file's disposition changes from clean to malicious12. References: 1: Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0, Module 4: Endpoint Protection and Detection, Lesson 4.1: Cisco AMP for Endpoints Overview, Topic 4.1.3: Retrospective Detection 2: Cisco AMP for Endpoints User Guide, Chapter: Retrospective Detection, URL: 3