Comprehensive and Detailed Explanation From Exact Extract:

Service Level Objectives (SLOs) are directly tied to user experience, and this connection is central to the SRE philosophy. The purpose of an SLO is to define how well a service must perform to keep users satisfied, without exceeding what is necessary or economically practical.

The Site Reliability Engineering Book, Chapter “Service Level Objectives,” states:

“The most important directive when defining SLOs is that they must reflect the expectations and needs of the users of the service.”

Similarly, the SRE Workbook, Chapter “Implementing SLOs,” highlights:

“SLOs are a tool to measure and control the reliability as experienced by the user.”

This makes it clear that SLOs are fundamentally user-centric. They are not based on internal engineering preferences, management goals, or operational convenience.

Why the other options are incorrect:

B. Management approval — SLOs are not driven by management goals but by user needs.

C. Change success rate — While related to reliability practices, change success is not the basis of SLO creation.

D. Toil reduction — Toil is unrelated to defining service-level targets.

Therefore, the correct answer is A.