An organization is using a Cisco FTD and Cisco ISE to perform identity-based access controls. A network administrator is analyzing the Cisco FTD events and notices that unknown user traffic is being allowed through the firewall. How should this be addressed to block the traffic while allowing legitimate user traffic?
A. Modify the Cisco ISE authorization policy to deny this access to the user
B. Modify Cisco ISE to send only legitimate usernames to the Cisco FTD
C. Add the unknown user in the Access Control Policy in Cisco FTD
D. Add the unknown user in the Malware & File Policy in Cisco FTD
