When Sean visited his grandparents in Edinburgh, Scotland, over the summer, he noticed that things he would normally buy at home in Alabama were much more expensive there. One morning, he used his credit card to purchase Starbucks coffee, which would normally cost $$4$ at home, but it showed on his credit card as $$6\mathrm{.}25$ when converted back to U$.$S$.$ dollars. Sean is experiencing a difference in the $\_\_\_\_\_\_\_\_$ between the United States and Scotland.

exchange rate

trade surplus

trade deficit

countertrade