The Central Bank of a country is the apex banking institution in a country.
The Central Bank supervises the working of all the commercial banks and formulates the monetary policy in an economy.
The Central Bank maintains the foreign exchange reserve by selling and buying foreign currencies in the open market to control the fluctuations of the foreign exchange rate.
All the foreign exchange transactions are controlled by the Central Bank.
The Central Bank also enforces the regulations formulated by the government in respect of foreign exchange control.
Final Answer: The Central Bank controls the foreign exchange transactions, buys and sells foregin exchange to maintain stability and enforces the regulations in this regard.