Correct Answer: Supply foreign exchange from its stock

Solution : The correct answer is (a)  Supply foreign exchange from its stock

Supply foreign exchange from its stock: The central bank can intervene in the foreign exchange market by supplying its stock of foreign currency reserves. By increasing the supply of foreign exchange, the central bank can help alleviate the upward pressure on the exchange rate.

The specific step taken by the central bank will depend on various factors, including the magnitude and duration of the exchange rate movement, the country's exchange rate policy framework, and the central bank's assessment of the situation.