The correct answer to this question is Understating the sales journal. Sales journals are used in accounting systems. They help track the customer's sales of items. These customers often owe a debt and a charged a receivable and credited a revenue. In other words, these journals record all of the sales made on credit.
The sales journal will include information like the date of the transaction, the account number, the name of the customer, invoice number, and the amount. Any sales made in cash are not recorded in the sales journal but instead recorded in what is known as the cash journal.