The correct answer is B - Sixteen characters with at least one letter, one number, and one symbol.
According to the WGU Cybersecurity Architecture and Engineering (KFO1 / D488) Study Guide, strong password policies must enforce a minimum length (preferably 12 to 16 characters) and require complexity, including uppercase and lowercase letters, numbers, and special characters. Sixteen-character passwords that include varied character types greatly increase the difficulty for attackers using brute-force or dictionary attacks.
Options A, C, and D either lack complexity or have too few characters, making them vulnerable to attacks.
Reference Extract from Study Guide:
"A strong password should be at least 12-16 characters long and include a mix of uppercase letters, lowercase letters, numbers, and special characters to maximize resistance to brute-force attacks."
- WGU Cybersecurity Architecture and Engineering (KFO1 / D488), Identity and AccessManagement Concepts