Comprehensive and Detailed Explanation From Exact Extract:

In the Full SRE model, reliability becomes a first-class citizen because SREs own the complete operational responsibility for the service and apply SRE principles end-to-end. The Google SRE Book describes several adoption models (Consulting, Embedded, and Full), and only the Full SRE model has SREs fully accountable for reliability outcomes.

From the Site Reliability Engineering Book, Chapter “SRE Engagement Models”:

“In the Full SRE model, the SRE team is responsible for end-to-end reliability. Reliability becomes a first-class objective, supported through SLOs, error budgets, and systematic reduction of toil.”

The Full model includes:

Full ownership of reliability

Enforcement of SLOs

Error budget policies

Engineering-driven improvement

Other models:

Consulting → SRE gives guidance but doesn’t own reliability

Embedded → temporary embedding to train teams, not full ownership

Platform → focuses on shared tooling, not service ownership

Thus, D. Full is correct.