Final answer:
Network Chuck used Metasploit, a penetration testing framework, to gain root access. Nmap, Netcat, and Wireshark are other networking tools used for different purposes such as auditing and analysis.
Step-by-step explanation:
The simple Linux tool that Network Chuck used to get root access is likely Metasploit. The options provided are different tools used for various network and security tasks. Specifically, Metasploit is a penetration testing framework that can be used to exploit vulnerabilities in systems to gain higher privileges such as root.
Nmap is used for network discovery and security auditing, Netcat is a networking utility for reading from and writing to network connections, and Wireshark is a network protocol analyzer. However, when it comes to gaining unauthorized access or increasing privileges on a targeted system, Metasploit fits the description best among the options listed.