What type of requirements include constraints that limit system functions?

The correct answer is non-functional requirements, which encompass constraints that limit how a system operates rather than what it does. Non-functional requirements define standards regarding performance, security, usability, reliability, and compliance among others. For example, a non-functional requirement might specify that a system must handle a certain number of users simultaneously or operate within a specific response time.

In contrast, functional requirements describe the specific behaviors or functions of the system, such as user authentication or data processing tasks. Business requirements focus on the high-level goals or needs of the organization, providing context but not detailing specific constraints on system functions. Implementation requirements relate to how the system is built or deployed, including technology choices or methods, rather than specifying operational constraints. Thus, non-functional requirements serve to guide the overall qualities needed from the system, making them essential for limiting system functions effectively.