Which of the following provides an IS auditor the BEST evidence that a third-party service...

Comprehensive and Detailed Step-by-Step Explanation:

Toverify the effectivenessof a third-party provider’ssecurity controls, anindependent external audit reportis thestrongestevidence.

Option A (Incorrect):Security configuration documentsare helpful butdo not confirm effectivenesswithout validation.

Option B (Incorrect):Policies and procedures outlineintent, but anaudit confirms actual implementation.

Option C (Correct):External audit reports (e.g., SOC 2, ISO 27001)provideindependent assurancethat security controls are effective.

Option D (Incorrect):Management interviews providequalitativeinsights but arenot objective evidenceof control effectiveness.