Pass the ISC2 CISSP.
Guaranteed.

1. A.Scanning and sandboxing email attachments with a secure email gateway or endpoint anti-malware before opening them
2. B.Implementing strict data access controls for project files (least privilege/RBAC)
3. C.Forwarding the email and attachments to the IT department after downloading them
4. D.Replying to the sender to request verification of identity

The scenario most strongly indicates a phishing attack delivering a malicious attachment that led to compromise and data exfiltration. A control that scans attachments and detonates them in a sandbox (for example, via a secure email gateway, EDR, or similar tooling) is designed to detect and block or contain malware before a user opens it, which would most likely prevent the initial compromise. Strict file access controls help limit who can access project data, but they do not reliably prevent malware running under the project manager’s own account from stealing data the manager legitimately can access. Forwarding the message to IT only after downloading/opening does not prevent execution of malicious content. Replying to request verification can still engage the attacker and does not stop malicious code embedded in an attachment from executing if it is opened.