Final answer:
The accounts receivable aging report is not part of the horizontal information flows in the B/AR/CR process; it's part of the vertical information flow, serving as a management tool.
Step-by-step explanation:
The question pertains to the horizontal information flows of the Billing/Accounts Receivable/Cash Receipts (B/AR/CR) process in an accounting system. The horizontal information flows involve the exchange of transactional data commonly occurring at the same level of an organization. In the choices provided, (a) accounts receivable aging report, (b) customer payment, (c) bank deposit, and (d) customer invoice, the option that is not a part of the horizontal information flows is (a) accounts receivable aging report. This report is actually part of the vertical information flow within an organization, serving as a management tool to assess the financial condition of the accounts receivable and not a part of the day-to-day transaction processing.