The correct answer is true. The '-Pn' option in Nmap disables host discovery, which means Nmap does not attempt to check if the host is online through methods like sending ICMP echo requests, a TCP ACK to port 80, or a TCP SYN to port 443, which is the default behavior when the '-Pn' option is not used. This is useful in situations where a firewall might be blocking these discovery packets, and there is a belief that the hosts are up and should be scanned.