Which of the following is a guideline for strong passwords?

A strong password is crucial for maintaining the security of accounts and sensitive information. A guideline that specifies a password must include uppercase letters, lowercase letters, numerals, and symbols is essential because it greatly increases the complexity and variability of the password. This diversity makes it much harder for attackers to guess or crack passwords through brute-force attacks or dictionary attacks, where common words or predictable patterns are used.

Using the various character types adds to the security by expanding the potential combinations and ensuring that simple passwords (such as those based on easily guessable personal information, common words, or predictable formats) are avoided. By adhering to this guideline, individuals can create stronger passwords that are more resistant to unauthorized access.

The other options do not provide adequate security measures for password creation and may lead to vulnerabilities. For instance, a password that is only five characters long is not strong enough due to the limited number of possible combinations, while excluding numbers weakens the complexity. Additionally, relying on common words or names makes a password susceptible to guessing attacks, as these are often the first types of passwords hackers will test.