Explanation:

• Contingency Fund (CF): This is a specific provision meant for meeting unexpected and unforeseen contingencies, including  Depreciation in the value of securities,  Risks arising out of monetary/exchange rate policy operations,  Systemic risks and any risk arising on account of the special responsibilities enjoined upon the Reserve Bank. This amount is retained within the RBI.
• The Currency and Gold Revaluation Account (CGRA): It is maintained by the Reserve Bank to take care of currency risk, interest rate risk, and movement in gold prices. 
• Investment Revaluation Account Foreign Securities (IRA-FS): The unrealized gains or losses on revaluation in foreign dated securities are recorded in the IRA-FS account.
• Investment Revaluation Account-Rupee Securities (IRA-RS): The unrealized gains or losses on revaluation is accounted for in Investment Revaluation Account-Rupee Securities (IRA-RS).

Hence option 4th is correct.