An architect has been working on a large project for the past 6 months.

The correct selection is A, D. A deployment rehearsal in a representative sandbox and final validation of the exact deployment package against production are the two strongest techniques for reducing last-minute release risk. They expose dependency, test, sequencing, and target-org issues before the limited go-live window. From a deployment perspective, the same release should be reproducible across environments, with dependencies, metadata/data differences, API behavior, and target-org constraints identified before production. Automation is valuable because it turns deployment knowledge into a controlled process rather than relying on memory or manual reconstruction. The other choices either rely on manual reconstruction, use a deployment mechanism designed for a different scope, or fail to preserve dependencies and repeatability across target environments. For this scenario, the decisive point is therefore the platform behavior represented by the selected options (A. Create a new sandbox and perform a test deployment to that environment.; D. Validate the final deployment package against production prior to go-live). Applying that rule consistently keeps the implementation aligned with Salesforce-supported lifecycle practices and makes the resulting change easier to review, validate, and operate across environments.

Study Guide reference: Deploying — Metadata API and Tooling API; deployment validation; package/change-set deployment; data migration; dependency management.