When an Auditor Selects a Sample of Items from the Vouchers

When an auditor selects a sample of items from the vouchers payable register for the last month of the period under audit and traces these items to underlying documents, the auditor is gathering evidence primarily in support of the assertion that

A) Recorded obligations were paid.
B) Incurred obligations were recorded in the correct period.
C) Recorded obligations were valid.
D) Cash disbursements were recorded as incurred obligations.