Comprehensive and Detailed Step-by-Step Explanation: Zero Trustis based on the principle of"never trust, always verify,"makingidentity validationthe most critical aspect. * Option A (Incorrect):Firmware updatesare important for security but are onlyone partof aZero Trustapproach. * Option B (Correct):Device and user identity validationensures that onlyauthorizedentities can accesscritical resources, reducing the risk of unauthorized access. * Option C (Incorrect):User awarenessis important but does not enforce access control, which isfundamentalto Zero Trust. * Option D (Incorrect):Encryptionsecures data but does not controlwho can access resources, which is the primary focus of Zero Trust. Reference:ISACA CISA Review Manual -Domain 5: Protection of Information Assets- CoversZero Trust security models and access control best practices.