When using third-party software developers, which of the following is the MOST effective method of providing software development Quality Assurance (QA)?

Retaining intellectual property rights is a legal and contractual protection measure, not a technical QA process that validates the quality or correctness of the software code.

Overlapping code reviews by both the client and the third-party developer create a collaborative QA process where defects, security vulnerabilities, and deviations from requirements are caught from multiple perspectives. This dual-review approach directly addresses software quality by technically examining the code itself rather than relying on administrative or environmental controls. It also ensures transparency and shared responsibility for the final product's integrity.

Having contractors attend development planning meetings ensures alignment on requirements and goals, but does not directly verify the quality of the code or software artifacts being produced.

Creating a separate contractor development environment addresses security isolation and access control concerns, but does not constitute a QA mechanism for validating software quality.