Which one of these statements related to the foreign exchange market is correct?

Currency trading floors are located in all the major financial centers of the world and operated by commercial banks.

SWIFT is a means of handling foreign currency transactions that is sponsored by a Belgian cooperative.

Currency trading floors are operated by the central bank of each country.

The foreign exchange market is second in size as a financial market only to the New York Stock Exchange.

The primary currency trading floor is located in London.