. A bank statement a. lets a depositor know the financial position of the bank as of a certain date. b. is a credit reference letter written by the depositor's bank. c. is a bill from the bank for services rendered. d. shows the activity which increased or decreased the depositor's account balance.

The answer is d. shows the activity which increased or decreased the depositor's account balance.

Explanation: A bank statement is a statement that shows the transaction activities of the depositor (customer) from the date the bank account is opened. It shows inflows (direct credit, deposits, transfers, etc) and outflows (direct debit, withdrawals, standing order, etc). Most the inflows and outflows are represented by Debit and Credit.

The bank statement therefore comprises transaction activity, debit, credit, balance columns. The balance shows if the account balance is increasing or decreasing. Customers can access the bank statement through online banking platforms or request for hard copy from their banks.