A “usability requirement” is:

A usability requirement specifies how usable a product or component must be, often in terms of effectiveness, efficiency, and user satisfaction, as defined in ISO 9241-11. These requirements ensure that the product meets specific human-centered design goals, such as allowing users to complete tasks accurately and quickly. Options A and C describe procedural or test setup elements, not actual usability requirements. Option B refers to personnel qualifications, which are not the same as usability requirements related to system behavior or performance.