Which type of testing would BEST demonstrate to clients that a completed security system '...

Site acceptance testing is the best choice because it verifies that the completed security system, once installed at the client’s location, meets the physical and functional requirements stated in the contract. This form of testing confirms that the system performs properly in the actual operating environment, where real conditions such as layout, user interaction, workflows, and site-specific risks can affect performance. In organizational and Human Resource related operations, this is important because employees, supervisors, and security personnel must rely on systems that function correctly in daily practice, not only in theory or in a factory setting. Factory testing may confirm equipment quality before delivery, but it does not fully prove contract compliance after installation. Therefore, site acceptance testing provides the most reliable demonstration to the client that all specified requirements have been met.