Refer to the Graph Above, Which Shows the Supply and Demand

Refer to the graph above, which shows the supply and demand for British pounds. D₁ and S₁ represent the initial demand and supply curves. If the supply of British pounds in the foreign exchange market shifts to S₃, and the British government wanted to fix the exchange rate at its initial level, then it should:

A) Sell U.S. dollars out of its reserves
B) Buy U.S. dollars to add to its reserves
C) Sell British pounds in the foreign exchange market
D) Buy British bonds in the open market