Use of cash register would not minimize threat of failure to bill, it is useful to minimize threat of theft of cash. Bar code and RFID technology would help to minimize threat of inventory lost and not threat of failure to bill. Restriction to access master data does not minimize threat of failure to bill rather minimizes financial fraud.

In order to minimize threat of failure to bill, it is necessary to separate billing and shipping functions so that control is divided between different individuals.

Thus, option (b), (c) and (d) is incorrect and option (a) is correct.