Poor password selection is frequently a major security problem for any system's security. Administrators should obtain and use password-guessing programs frequently to identify those users having easily guessed passwords.
Because password-cracking programs are very CPU intensive and can slow the system on which it is running, it is a good idea to transfer the encrypted passwords to a standalone (not networked) workstation. Also, by doing the work on a non-networked machine, any results found will not be accessible by anyone unless they have physical access to that system.
Out of the four choice presented above this is the best choice.
However, in real life you would have strong password policies that enforce complexity requirements and does not let the user choose a simple or short password that can be easily cracked or guessed. That would be the best choice if it was one of the choice presented.
Another issue with password cracking is one of privacy. Many password cracking tools can avoid this by only showing the password was cracked and not showing what the password actually is. It is masking the password being used from the person doing the cracking.
Source: National Security Agency, Systems and Network Attack Center (SNAC), The 60 Minute Network Security Guide, February 2002, page 8.
