For the use case where a library application displays a read-only list of outstanding past-due books to staff during the book request case process, the appropriate Data Page configuration needs to ensure the data is accessible and specific to each user session without the possibility of modification.

D. List, Readonly, Requestor: This configuration is optimal for the described scenario. A 'List' type is suitable because it involves displaying multiple records (outstanding books). 'Readonly' ensures that the data cannot be altered during the process, maintaining the integrity of the information displayed. The 'Requestor' scope is chosen because the information needs to be specific to the user session, providing a personalized reminder for the staff member to notify the member about their past-due books.

Options involving 'Page' (B, C, E) are not suitable as they are designed for single records rather than lists. 'Editable' (B, E) permissions are unnecessary and potentially problematic for this use case since the data should not be modified. 'Node' scope (F) would not provide the user-specific session data needed for this functionality.