Which switch tells Nmap to scan all possible ports from 1 to 65535?

• A. -F
• B. -p-
• C. -p80
• D. -sV

Answer: (B)

To scan every possible port, you need a switch that specifies the full port range. In Nmap, -p- means scan all ports from 1 through 65535. This is the exact coverage you’re asking for, and it’s useful when you want a complete picture of what services might be listening on any port, though it will take longer than more targeted scans.

Other options behave differently: -F performs a fast scan of the top 100 ports, not the full range; -p80 targets only port 80, so it misses everything else; -sV is about detecting the versions of services after a port is found, not about which ports to scan. So -p- is the right choice for exhaustive port scanning. If you prefer a fully explicit form, you could also use -p1-65535.