1.The RBI (Reserve Bank of India) can influence money supply by changing the "Bank Rate" at which it gives loans to commercial banks

2. The Bank Rate is an important tool used by the central bank to control the money supply in the economy. 

3.When the RBI lowers the Bank Rate, it becomes cheaper for commercial banks to borrow money from the central bank, which can lead to an increase in the money supply in the economy. Conversely, when the RBI raises the Bank Rate, it becomes more expensive for commercial banks to borrow, potentially reducing the money supply.

So, the correct option is (4) Bank Rate at which it gives loans to the commercial banks.