Which of the following processes is must at the end of each project phase to determine the completeness of the project work and to gain the customer's acceptance to move the project forward?

Scope Verification (called Validate Scope in PMBOK 5+) is the process of formalizing acceptance of completed project deliverables by the customer or sponsor. It is performed at the end of each project phase to confirm that all work meets the defined scope requirements and to obtain the formal authorization needed to proceed to the next phase.

Inspection of key results is a tool or technique applied within quality control, not a standalone formal process that governs phase completion and secures customer acceptance.

Quality control focuses on monitoring outputs against quality standards to identify defects, but it does not involve formal customer acceptance of deliverables as a gate for moving forward.

A phase gate review is a governance decision checkpoint evaluating whether the project should continue, change, or stop - it is not the dedicated process for verifying scope completeness and obtaining customer acceptance.