Comprehensive and Detailed Explanation:

In Zero Trust architecture (ZTA), the principle is “never trust, always verify.” The most important aspect for an IS auditor to evaluate is whether access control policies are properly designed, aligned with industry standards, and consistently enforced. These policies define how identities, devices, and contexts are authenticated and authorized before gaining access.

Option A: Perimeter firewalls are less relevant in Zero Trust, which minimizes reliance on network boundaries.

Option C: Access reviews are important but are periodic, not continuous enforcement.

Option D: Secure remote protocols are necessary but part of broader access policy enforcement.

Option B: Correct — policies are the foundation of Zero Trust security.

???? ISACA Reference: ISACA’s “Zero Trust and Audit Considerations” guidance; CISA Review Manual 27th Edition, Domain 5, section on identity, access, and authentication controls.