The best answer is C. Ensure every Increment meets them.  Non-functional requirements (NFRs) are system qualities that guide the design of the solution and often serve as constraints across the relevant backlogs 1 .  NFRs are persistent qualities and constraints typically revisited as part of the definition of done (DoD) for each Iteration, PI, or release 1 . The Scrum Team should ensure that every Increment meets the NFRs, as they are part of the product requirements and affect the value delivery and customer satisfaction.