Q.Which of the following institutions is the central bank of India?
(A) State Bank of India
(B) Reserve Bank of India
(C) Industrial Development Bank of India
(D) National Bank for Agriculture and Rural Development

India has exactly one apex bank that controls the whole banking system and manages the nation's currency and credit — the others listed are ordinary or specialised banks, not the central bank.

The State Bank of India is a commercial bank; IDBI and NABARD are specialised development/refinance institutions. Only the RBI, established under the RBI Act, 1934, sits at the apex with the sole right to issue currency and control credit.

As Section a explains, a country has only ONE central bank — the apex institution that controls and supervises the entire banking and monetary system and manages the nation's money and credit in the public interest, without seeking profit.

In India this is the Reserve Bank of India (RBI), set up under the Reserve Bank of India Act, 1934, and functioning from 1 April 1935. It alone has the sole right to issue currency notes, acts as banker to the government and to the banks, and controls credit.

The other options are all ordinary or specialised banks, not the central bank: the State Bank of India (A) is a commercial bank that deals directly with the public; the Industrial Development Bank of India (C) and the National Bank for Agriculture and Rural Development (D) are specialised development/refinance institutions. None of them performs the apex central-banking role.

Students sometimes pick the State Bank of India because it is large and government-associated. Remember: size does not make a bank the central bank — only the RBI is the apex authority with note-issue and credit-control powers; SBI is simply a big commercial bank.