Which of the following is not a function of commercial banks ?

The correct answer is option (2) : Controls money supply

Controls money supply is not a function of commercial banks. The control of the money supply is typically a function of central banks, which set monetary policy to achieve economic goals such as price stability and full employment.

Commercial banks play a role in the money supply through their lending and deposit activities, but the direct control and regulations of the money supply fall under the purview  of the central bank.