The network administrator suspects that packet sniffing is being used to capture data packets in the network. The network administrator is using an SSH connection for all critical applications, and switches are being used on all network connections. Should the network administrator be concerned

Yes the network administrator should be concerned if he suspects packet sniffing

Explanation:

packet sniffing is the process of capturing data that is sent over a local network. From the scenario above, the network administrator is using an SSH connection for all critical applications, however SSH which is Secure Shell (SSH) is a UNIX-based command interface and protocol for securely getting access to a remote computers and may not provide effective prevention of packet sniffing in a local network