Which of the following tools is used primarily for network exploration?

Nmap is primarily used for network exploration and security auditing. It serves as a powerful open-source tool that allows users to discover hosts and services on a network by sending packets and analyzing the responses. Its capabilities include identifying live hosts, detecting open ports, and even determining the operating system of devices on the network. This makes it particularly useful for mapping out networks and gaining insights into their configurations, which is essential for both security assessments and network management.

In contrast, while Wireshark is a network protocol analyzer that captures and analyzes packet data transmitted across a network, its main focus is on traffic analysis rather than systematic exploration. Kali Linux is a penetration testing platform that includes a variety of security tools but is not specifically designed for network exploration itself. Metasploit is a framework focused on exploiting vulnerabilities in systems and applications, which serves a different purpose in the realm of cybersecurity. Nmap stands out for its primary function of network exploration, making it the correct choice in this context.