Which of the following provides the MOST assurance that a third-party hosting provider will be...

A Service Level Agreement (SLA) is the contractual document that specifies and guarantees the availability levels the third-party hosting provider must meet. It provides the clearest and most enforceable commitment to availability.

“SLAs establish measurable commitments that can be monitored and enforced, providing a high level of assurance that service availability will meet business requirements.”

— CISM Review Manual 15th Edition, Chapter 3: Information Security Program Development and Management, Section: Outsourcing and Third-Party Management*

ISACA’s practice questions highlight SLAs as the most direct and reliable assurance for third-party service availability.