Final answer:
The fundamental differences in the common and code systems can cause difficulty in determining laws governing export and import.
Step-by-step explanation:
The fundamental differences in the common and code systems can cause difficulty in determining laws governing export and import, as option b states. The common law system, followed in countries like the United States, relies on legal precedents and case law to interpret and develop the law. On the other hand, the code system, followed in countries like France, relies on comprehensive legal codes that cover different areas of law. These differences can lead to challenges in harmonizing laws related to international trade and creating agreements between countries.