Which actions could cause accounts receivable (A/R) and accounts payable (A/P) accounts to be over- or understated?

Recording a bill payment, then deleting the original bill can lead to discrepancies in accounts receivable and accounts payable. When a bill is properly recorded, it establishes a liability which subsequently affects accounts payable. If a payment is made against a bill that is then deleted, the payment remains in the system as an outflow without a corresponding bill to justify it. This results in an understatement of accounts payable, as the liability is removed without recognizing the payment made against it. This action creates inconsistency in the accounting records, leading to potential cash flow issues and incorrect financial reporting.

In contrast, the other scenarios—like posting payments to income or confusing expense postings—highlight different points of mismanagement but do not specifically illustrate the direct relationship between bill payments and their corresponding bills in the context of A/R and A/P balances as effectively as the first choice.