Bank rate means the rate of interest

The correct answer is (d). Bank rate is the rate of interest at which the Reserve Bank of India lends money to commercial banks. It is the benchmark interest rate in India and is used by banks to set their own lending and deposit rates.

(a) is incorrect because the rate of interest paid by banks to depositors is called the deposit rate.
(b) is incorrect because the rate of interest charged by banks from borrowers is called the lending rate.
(c) is incorrect because the rate of interest charged on inter-bank loans is called the inter-bank rate.