What document must accompany a shipper's declaration under IMDG and ICAO?

The correct choice is the transportation document, which is essential under both IMDG (International Maritime Dangerous Goods Code) and ICAO (International Civil Aviation Organization) regulations. The transportation document serves as a critical record that confirms the shipment details and provides important information about the nature of the goods being transported, including those classified as dangerous.

In the context of hazardous materials, the transportation document is necessary to ensure compliance with safety protocols, detailing the specifics of the shipment, emergency response procedures, and the proper handling of the material throughout the transportation process. It acts as an official authorization for the carrier to transport the goods and is crucial for regulatory compliance.

Other documents, while relevant in certain contexts, do not fulfill this specific requirement. An invoice may outline the transactional details, a certificate of origin verifies the source of goods, and a customs declaration facilitates the clearance of cargo through customs. These documents serve different purposes and do not replace the need for a transportation document when it comes to accompanying a shipper's declaration under IMDG and ICAO.