Final answer:
The Cardholder's Receiving Official (CRO) is responsible for verifying proof of delivery for Governmentwide Commercial Purchase Card transactions during the monthly transaction review.
Step-by-step explanation:
The responsibility for verifying proof of delivery for all Governmentwide Commercial Purchase Card transactions during the monthly transaction review lies with the Cardholder's Receiving Official (CRO). The CRO is responsible for ensuring that the goods or services have been received and meet the stated specifications before approving the transaction. They confirm the receipt by signing the delivery receipt or other supporting documentation, which serves as proof for the transaction.