What is necessary for an export carrier to load cargo?

In the context of exporting goods, the necessity for a shipper's export authorization stems from regulatory compliance requirements. The shipper’s export authorization is a critical document that grants permission for the export of specific items and ensures adherence to export controls and regulations established by government authorities. Without this authorization, an export carrier cannot legally load the cargo, as it signifies that the goods comply with applicable laws and regulations specific to export.

The other options, while important in the export process, do not specifically serve the same legal function. A valid bill of lading is essential for the transportation of goods and provides proof of shipment but does not authorize the export itself. Insurance documentation is crucial for protecting the cargo during transit but is not a prerequisite for the loading process. A shipper's signed contract outlines the agreement between the parties involved but does not replace the need for export authorization. Thus, the shipper’s export authorization is essential for ensuring that all cargo is loaded in compliance with the law.