When a Development Team is having trouble delivering a working Increment because they don’t understand...

The correct answer is C, because when a Development Team is having trouble delivering a working Increment because they don’t understand a functional requirement, they should collaborate with the Product Owner to determine what is possible and acceptable. The Scrum Guide states that “the Product Owner is responsible for maximizing the value of the product resulting from work of the Development Team. How this is done may vary widely across organizations, Scrum Teams, and individuals.” Therefore, the Product Owner should clarify the functional requirement and negotiate the scope of work with the Development Team.