Final answer:
Chris can use the netstat command-line tool to gather information about other systems on the local network without installing additional tools or sending additional traffic. Another useful tool is nmap. Therefore the correct option C. nmap
Step-by-step explanation:
The command-line tool that Chris can use to gather information about other systems on the local network without installing additional tools or sending additional traffic is netstat. Netstat is a built-in command-line tool in most operating systems that displays active network connections, listening ports, and other network-related information. By running the 'netstat -a' command, Chris can view a list of active connections to identify potential database and web servers.
Another useful command-line tool for network reconnaissance is nmap. Nmap allows Chris to scan the network for open ports, services running on those ports, and even detect the operating system of target machines. By running the 'nmap -sS -p 80,443 ' command, Chris can identify web servers that are accessible on ports 80 and 443.
Both netstat and nmap are valuable tools in performing network reconnaissance to gather information about systems on a local network.
Therefore the correct option C. nmap