Why would an international e-commerce marketer consider adding a "buffer margin" to product prices in certain markets?

a. the us$/foreign currency exchange rate is higher than 1, and the marketer needs to cover the additional currency conversion costs.
b. the harmonized compliance rate is lower than 1, and the marketer needs to cover the additional currency conversion costs.
c. the us$/foreign currency exchange rate is less than 1, and the marketer needs to cover the additional currency conversion costs.
d. the harmonized compliance rate is higher than 1, and the marketer needs to cover the additional currency conversion costs.