The book recommends that passwords be at least ________ characters long.

• A. 6
• B. 20
• C. 8
• D. 100

Answer: (C)

Longer passwords dramatically increase the difficulty of guessing them, because each extra character multiplies the number of possible combinations. Setting a minimum length helps ensure passwords aren’t trivially brute-forced or guessed from common patterns. Eight characters is a practical minimum that balances security with memorability in many standard guidelines. Six characters would be too weak today, since automated attackers can exhaust that space quickly. Twenty or a hundred characters, while stronger, are impractical for everyday use and burden users. So, eight characters serves as a reasonable baseline among the given options, with the best chances of resisting common attack methods while remaining manageable to remember or store securely. If you can, go longer and consider using a password manager and multi-factor authentication for added protection.