Which two primary sources provide feedback for creating, altering, and prioritizing backlog items?

The correct answer highlights the significance of incorporating feedback from testing and customer evaluation into the development process. Testing provides insights about the functionality and performance of the product, while customer evaluation captures direct user experiences and satisfaction levels. These two elements are crucial in shaping the backlog because they align the development with real-world usage and expectations, ensuring that the highest priority items bring the most value to end-users.

In contrast, while sponsor and business representatives can contribute valuable perspectives, their feedback may not encompass the practical insights gained through actual testing or customer interactions. Similarly, surveys and interviews can provide contextual information, but they typically do not offer the same immediacy or actionable feedback that comes from direct testing outcomes or evaluations by customers using the product. Reviews and retrospectives are important for reflecting on past iterations but are often more focused on process improvement rather than directly informing the current backlog priorities. Thus, testing and customer evaluation serve as the most relevant sources for backlog refinement.