What do non-functional requirements describe?

Non-functional requirements are critical in the field of software development, as they outline the characteristics that a system should possess rather than specifying particular behaviors or functions. These requirements describe qualities such as performance, usability, reliability, scalability, and security. They set the standards and expectations for how a system should operate, influencing the user experience and satisfaction.

For instance, a non-functional requirement might specify that a web application should load within three seconds, or that it must support a minimum of 1000 concurrent users without degradation in performance. This focus on attributes is essential for ensuring that the solution not only meets its functional aspects but also provides a satisfactory experience for users.

The other options primarily focus on aspects that are not aligned with the definition of non-functional requirements. While option A refers to specific tasks (which are functional requirements), option B discusses computational resources, and option D lists programming languages, none of these capture the essence of what non-functional requirements aim to describe.