Which of the following represents an example of an IT application control?

a. The assistant controller performs a monthly bank reconciliation and follow-up of unexpected outstanding items.

b. The accounts receivable manager reviews credit balances in accounts receivable quarterly to determine their causes.

c. The software application compares all sales invoices with underlying shipping information on the bills of lading and packing slips with sales invoices. If differences are revealed, a report is generated for review and follow-up by the billing supervisor.

d. All changes to software applications must be reviewed and approved by the department affected by the application.