To analyze malware behavior in detail, the best approach is toexecute the malware in a sandbox (D) andcapture its network activity. This providesreal-time analysisof how the malware behaves, spreads, and communicates.
This method is highlighted inDomain 2.1under"Analyzing indicators of compromise"and usingsandboxing and packet captureto study malware.
Reference: CompTIA Security+ SY0-701 Objectives, Domain 2.1 - "Indicators of malicious activity: Perform packet captures; sandboxing for malware analysis."