Country Y is Country X's sole trading partner. Which of the following would increase the current account of Country X?
a. The central banks of Country X and Country Y reduce the money supply to increase interest rates.
b. The currency of Country Y depreciates against the currency of Country X.
c. Country X imposes tariffs on imports from Country Y, and Country Y retaliates by imposing an identical tax on imports from Country X.
d. The currency of Country X depreciates against the currency of Country Y.
