A user has reported application connectivity problems to the network administrator. The network administrator knows there have been firewall configuration changes recently by a security vendor and believes the issue could be related to a port being closed on the firewall. Which of the following should the network administrator do NEXT? 

Answer options:

A. See if the same application fails on another workstation
B. Go into the firewall and open the port
C. Verify system functionality on the user`s workstation
D. Document the issue for future reference

C