The RBI can influence money supply by changing the rate at which it gives long-term loans to commercial banks. This rate is called the ......

Bank Rate.

The correct answer is Option (2) → Bank Rate.

Bank Rate is the rate at which the Reserve Bank of India (RBI) provides long-term loans to commercial banks without any collateral. By changing the bank rate, the RBI can influence the money supply and overall credit conditions in the economy.

Explanation of other options:

Reverse Repo Rate – This is the rate at which the RBI borrows money from commercial banks for a short term. It's used to absorb excess liquidity from the system.

Cash Reserve Ratio (CRR) – This is the percentage of total deposits that banks are required to keep with the RBI. It affects liquidity but is not an interest rate or lending instrument.

Repo Rate – This is the rate at which the RBI lends to commercial banks for short-term needs, usually with government securities as collateral. It is not used for long-term lending.