Which control can provide the best assurance in regards to the management of internal controls for a service provided by a third party?

The best assurance regarding the management of internal controls for a service provided by a third party is provided by a comprehensive independent third-party audit report. This type of audit is objective and thorough, carried out by an external entity that is not affiliated with the organization or the service provider. Such audits typically assess the design and operational effectiveness of internal controls, ensuring they meet relevant standards and regulatory requirements.

The independent nature of the audit brings credibility and a level of trust that internal assessments or reviews may not achieve, as they might lack impartiality. Furthermore, these audit reports often provide insights into compliance with industry standards such as SSAE 18, which can be critical for understanding the risk management practices and control environments of third-party providers.

While other options like service level agreement reviews, user satisfaction surveys, or quality assurance programs contribute to monitoring and improving service quality and performance, they do not focus specifically on the auditing of internal controls with the same level of rigor and independence as a comprehensive third-party audit.