Which of the following is NOT a likely implication for supply chain planners of the presence of trading blocs' across the world?
a. Planning can be conducted at a larger regional level instead of only at the country level
b. Some countries in the trading bloc might have lower customs duties and hence might influence supply chain planning
c. U Trading Blocs always make it more difficult for foreign firms to do business there
d. Warehouses and distribution centers can be set up to cater to a larger geographical area