During a normal business day, a network administrator is alerted to performance degradation affecting several critical servers. After an initial review, no configuration changes or recent updates are linked to the issue. What should be the administrator's NEXT step in applying the 'divide and conquer' principle to troubleshoot this network performance anomaly?
Examine performance statistics and logs on the core router that interconnects the critical servers.
Reboot the servers one by one during off-peak hours to see if performance improves.
Run updated antivirus and malware scans on all critical servers to ensure no malicious software is causing the issue.
Conduct a thorough examination of server logs to identify any unusual activity or error messages.