Which Nmap option would you use if you were not concerned about being detected and wanted to perform a very fast scan?

The Nmap `-T` option specifies the timing template for a scan, with values ranging from `0` (Paranoid) to `5` (Insane). `-T5` sets the "Insane" timing template, which performs a very aggressive and fast scan by sending probes rapidly and not waiting long for responses, making it ideal when detection is not a concern and speed is paramount.

The `-O` option enables OS detection, which can slow down a scan and is not primarily focused on speed.

The `-T0` option sets the "Paranoid" timing template, which is extremely slow and designed for stealth, directly contradicting the requirement for a fast scan without concern for detection.

The `-A` option enables aggressive scan options, including OS detection, version detection, script scanning, and traceroute, which can be comprehensive but also very slow, not primarily designed for maximum speed.