Which of the Following Is $\underline{\text{ not }}$ A Reason Why International Trade Has Increased as a Proportion

Which of the following is $\underline{\text{ not }}$ a reason why international trade has increased as a proportion of the world GDP in the last 30 years?

A) The reduction in transportation costs
B) The advent of the Internet and the subsequent reduction in the cost of doing international business
C) Reductions in government restrictions on trade between countries
D) All of the above are relevant in explaining the growth of international trade.
E) None of the above are relevant in explaining the growth of international trade.