What type of testing is aimed at verifying that a system meets its functional requirements?

Functional testing is a type of testing focused specifically on assessing whether a software application or system operates in accordance with its specified functional requirements. This type of testing ensures that all features work as intended and that the system behaves as expected under various conditions. It involves activities such as verifying user interactions, checking system outputs, and examining how the system processes inputs to confirm that it meets both user and system expectations.

This approach is crucial in the software development lifecycle, as it helps identify and rectify any discrepancies between the expected and actual functioning of the system. By conducting functional testing, organizations can ensure that business requirements are met, leading to a higher quality product that satisfies customer needs.

While the other options like performance testing, compliance testing, and vulnerability testing serve important roles in evaluating aspects of the system, they do not primarily focus on validating the functional requirements. Performance testing assesses how the system performs under load, compliance testing verifies adherence to external regulations or standards, and vulnerability testing checks for security weaknesses, which are all different from the primary aim of functional testing.