File Integrity Monitoring (FIM) detects unauthorized changes to files, including deletions, modifications, and permission alterations. When protecting shared data, FIM creates baseline hashes of files and monitors them for unexpected changes. Any deviation triggers alerts, enabling rapid investigation and remediation.

Security+ SY0-701 identifies FIM as a crucial tool for:

Integrity monitoring

Detecting unauthorized file deletion

Identifying malicious or accidental permission changes

Supporting compliance (PCI-DSS, HIPAA, etc.)

DLP (A) protects against data leakage but does not detect permission misconfiguration or deleted files. EDR (B) monitors endpoint activity but is not optimized for shared file integrity. ACL (D) defines permissions but does not track changes.

Thus, C (FIM) is the correct solution.