Choice "D" is correct. Reconciling control totals for sales invoices with the accounts receivable subsidiary ledger is not an effective control related to the billing process, since errors that exist in the preparation of invoices would likely carry through to accounts receivable.
Choice "c" is incorrect. Comparing shipping totals with sales invoice totals is an effective control to reduce billing errors.
Choice "b" is incorrect. Computer controls related to pricing and mathematical accuracy will reduce billing errors.
Choice "a" is incorrect. Matching shipping documents with approved sales orders ensures that invoices are properly authorized and only goods ordered have been shipped.
