An increase in foreign reserves is the correct answer. A surplus in the balance of payments means that a country is earning more from its exports and foreign investments than it is spending on imports and foreign investments. This leads to an inflow of foreign currency into the country, which increases its foreign reserves. Therefore, "Increase in foreign reserves," is the correct answer. A surplus in the balance of payments may or may not directly affect the government budget surplus, and it does not lead to a decrease in foreign reserves.