正解:D
Taking snapshots of virtual machines (VMs) is one of the most effective techniques for preserving digital evidence in a cloud environment. Snapshots capture the entire state of a VM, including its memory, configuration, and disk contents at a particular point in time. This allows investigators to preserve evidence as it was at the moment of the incident, enabling detailed analysis without altering the original state of the system.
While isolating the compromised system is important to prevent further damage, snapshots are more directly useful for preserving evidence. Backing up data and analyzing management plane logs are also valuable for incident response, but they don't capture the complete state of a compromised system as effectively as snapshots do.