The mandatory minimum amount a company must deposit by 30th April each year in its Deposit Repayment Reserve, as a fraction of next-year maturing deposits, is:

1. Rule 13 prescribes that the company must deposit, on or before 30th April, an amount not less than 20% of the deposits maturing during the following financial year. 2. This is a continuing obligation till all deposits are repaid. 3. Hence (C). _Source: ICAI BoS CA Inter Paper 2 — Acceptance of Deposits_