What aspect of valuation changes depending on the date of export?

The correct choice highlights that currency conversion is influenced by the date of export because exchange rates fluctuate over time. When goods are exported, their value in foreign currency needs to be converted into the reporting currency, typically through the prevailing exchange rate at the time of export. Since exchange rates can vary significantly from one day to the next due to various economic factors, the valuation of goods can change based on when they are exported. This can directly affect the duties and taxes assessed on the goods when they arrive in the destination country.

Country of origin and duty rates are more static factors, as the country of origin remains constant for a product, while duty rates are often established based on trade agreements and regulations that do not change daily. Fees might have scheduled amounts or fixed structures that are not usually contingent on the specific date of export. This underscores why currency conversion is the most relevant aspect that changes with the date of export.