The correct answer is A. reduce CRR.
CRR stands for Cash Reserve Ratio. It is the percentage of the total deposits that banks are required to keep with the Reserve Bank of India (RBI). When the RBI reduces the CRR, banks have more money to lend. This can encourage investment in the country, as businesses will have more access to credit.
Option B is incorrect. Increasing the CRR would make it more difficult for banks to lend money, which would discourage investment.
Option C is incorrect. Selling securities in the open market would reduce the amount of money in the banking system, which would also discourage investment.
Option D is incorrect. Increasing the bank rate would make it more expensive for banks to borrow money from the RBI, which would also discourage investment.