Which of the following open source tools would be the best choice to scan a network for potential targets?

NMAP is purpose-built for network reconnaissance, supporting host discovery, port scanning, service enumeration, OS detection, and scripted vulnerability checks across entire subnets. Its flexibility and depth make it the canonical tool for mapping a network and identifying live hosts, open services, and potential attack surfaces.

NIKTO is a web application vulnerability scanner that tests HTTP servers for misconfigurations and known issues, not a general-purpose network host discovery tool.

Cain and Abel is a Windows-based password recovery and network credential sniffing tool, not designed for broad network scanning or target enumeration.

John the Ripper is a password cracking utility focused on offline hash-cracking via brute-force or dictionary attacks and performs no network scanning functions.