An NGFW alerts that a web server in the DMZ is sending suspicious traffic. A network administrator finds that port 25 is open, and the traffic is originating from this port. The only purpose of this server is to deliver website traffic. Which of the following should the network administrator recommend to the systems administrator? 

Answer options:

A. Disable Telnet service on the server.
B. Disable DHCP service on the server.
C. Disable the SMTP service on the server
D. Disable FTP service on the server.

C