Which statement illustrates a well-written requirement?

The statement that illustrates a well-written requirement is characterized by its clarity, specificity, and the way it defines a user interaction with a system. The chosen statement indicates a clear user action – selecting an option – contingent upon a specific condition (the display of the "Authorization is Required" notice). This allows for precise understanding of both the context in which the requirement applies and the expected system behavior.

A well-written requirement should define what the system must do in clear terms while leaving no ambiguity about conditions and outcomes. The reference to a specific user action in response to a certain system state provides clear guidance for developers and testers and ensures that the requirement can be tested effectively.

In contrast, the other statements lack the necessary specificity or clarity. For example, the second statement is vague in terms of any conditions attached to the ability to cancel an order, making it less useful for implementation. The third statement is more of a goal than a specific requirement, lacking clear parameters for action or outcome. The fourth statement, while clear, does not convey a user action or requirement as effectively as the first. It also lacks an explicit context for the user’s interaction with the system.