Systems are communicating with unknown external entities, raising concerns about exfiltration or malware.

CEH v13 highlights behavioral analytics as one of the most effective techniques for identifying ambiguous or stealthy threats such as data exfiltration, command-and-control traffic, and insider abuse. When interactions appear suspicious but not definitively malicious, behavioral profiling provides the most direct visibility.

Behavioral analytics tools establish a baseline of normal system and network behavior, including typical communication patterns, data transfer volumes, destinations, and timing. Deviations from this baseline trigger alerts, allowing analysts to detect previously unknown threats without relying on signatures.

Option C is the most appropriate because it both identifies anomalies and supports continuous mitigation. A full zero-trust shutdown (Option A) is disruptive. Forensics (Option B) is reactive and better suited after confirmation of compromise. Training (Option D) does not address system-level interactions.

CEH v13 emphasizes that modern attacks often blend into normal traffic, making behavioral analysis essential. Therefore, Option C is the correct answer.