The correct answer is RBIAbout RBI:?The Reserve Bank of India was established on 1st April 1935. It is the central bank of India that controls all the banks in the country. Was established on the recommendation of the Hilton Young Commission. The RBI was nationalized with effect from 1st January 1949. Four local boards of RBI are located in four regions of the country Mumbai, Delhi, Chennai, and Kolkata. The central office was initially established in Calcutta but was permanently moved in 1937 to Mumbai. RBI is headed by the Governor, current (as of April 2021) Governor of RBI is Shri Shaktikanta Das (25th Governor)The first Indian Governor of RBI was CD Deshmukh. Also known as Banker's bank, Banker to the government. Functions of RBI:?Issue currency,Control credit,Acts as National Clearinghouse. Raghuram Rajan (23rd) and Urjit Patel (24th) former Governor of RBI. Additional InformationAbout SBI: (as of 2021) State Bank of India (SBI) a Fortune 500 company, is an Indian Multinational, Public Sector Banking and Financial services statutory body. Headquartered in Mumbai. Established in: 1955Current Chairman: Dinesh Kumar Khara (as of April 2021)About Union Bank: (as of 2021)?Headquartered in Mumbai. Established in: 1919MD & CEO: Shri Rajkiran Rai G. About CBI: (as of 2021)?CBI is the premier investigative agency in the country. Established in 1963. Current head (Intreme Chief) Praveen Sinha