The best answer is D because in Windows security group membership events, the field that identifies the account actually added to or removed from the group is the Member ID field. The Target Account Name refers to the group being modified, not the user or object inserted into or deleted from that group. Caller User Name identifies the subject who performed the action, which is useful for attribution, but it does not identify the changed member itself. The first line of the event description is not a reliable field-level answer because the question asks for the specific data element. This aligns with the CHFI v11 objectives on event logs, evaluating account-management events, and log files as evidence. In practice, forensic analysts must separate three things in a group change event: the actor who made the change, the group that was affected, and the member object that was added or removed. Microsoft’s auditing documentation for these events shows that Member identifies the distinguished name or SID-linked object involved in the membership change. For exam purposes, that makes Member ID the most precise and defensible choice.