The correct answer is 75%.

• The assets in India of every banking company at the close of business on the last Friday of every quarter or, if that Friday is a public holiday under the Negotiable Instruments Act, 1881 (26 of 1881), at the close of the business on the preceding working day, shall not be less than seventy-five percent. 

• Every banking company shall, within one month from the end of every quarter, submit to the Reserve Bank a return in the pre­scribed form and manner of the assets and liabilities referred to in sub-section
  • as at the close of business on the last Friday of the previous quarter, or, if that Friday is a public holiday under the Negotiable Instruments Act, 1881 (26 of 1881) at the close of business on the preceding working day.
• Banking Regulation Act, 1949:-
  • Banking ​means accepting, for the purpose of lending or investment, of deposits of money from the public, repayable on demand or otherwise, and withdrawal by cheque, draft, order, or other wise.
  • It was enacted on 10 March 1949 and provides a regulatory framework for commercial banks. 
  • This act empowers RBI to regulate commercial banks.