The correct answer is false. When using '-p-' with Nmap, it instructs Nmap to scan all 65535 TCP ports. It is not limited to the ports listed in the /etc/services file. This is a common misunderstanding as the /etc/services file contains well-known ports and service names, but Nmap's '-p-' option bypasses this listing and targets all possible TCP ports, hence providing a comprehensive scan.