Which of the following are well known password-cracking programs?

L0phtcrack is a well-established Windows password cracking tool that recovers passwords from LM and NTLM hashes using dictionary, brute-force, and hybrid attacks. It has been widely referenced in security literature and used in real-world attacks since the late 1990s.

NetCat is a general-purpose network utility for reading and writing data across TCP/UDP connections, not a password cracking tool.

'Jack the Ripper' is not a real security tool; the actual well-known password cracker is named 'John the Ripper', making this a deliberate distractor.

Netbus is a Remote Access Trojan used for unauthorized remote control of compromised systems, not a password cracking program.

John the Ripper is one of the most popular open-source password cracking tools, supporting dozens of hash types and multiple attack modes including wordlist and brute-force across Unix, Windows, and other platforms. It is considered a standard reference tool in the security community.