The correct answer is 'Running a file system check during a boot time on the partition mounted as /home'. This is because running file system checks can potentially disrupt user access to files. Performing these checks during boot time ensures user directories are not in use, preventing potential data loss or corruption. Mounting the partition as read-only won't accomplish a file system check but will prevent changes. Scheduling a cron job for file system check will still affect users if they are logged in and using their directories. Although usermod can manipulate user accounts, it doesn't facilitate a file system check on the /home directories.