The main answer to the question is option b) its tariff classification.
Explanation: Tariff classification is a system used to categorize products based on their characteristics, such as the materials used, the purpose of the product, and its composition. This classification system helps determine the rule of origin for a product undergoing a transformation in North America. The rule of origin is important because it determines the eligibility of a product for preferential treatment under trade agreements.
For example, if a product is classified under a certain tariff code that requires a certain percentage of value to be added in North America, it would need to meet that requirement to be considered as having originated in North America.
In conclusion, the rule of origin for most products undergoing a transformation in North America is based on their tariff classification.