Choice "D" is correct. Income statement accounts tend to be more predictable than balance sheet accounts, and therefore interest expense would likely yield a higher level of evidence than the allowance for doubtful accounts, accounts receivable, or accounts payable.
Choice "b" is incorrect. The allowance for doubtful accounts is affected by write-offs of specific receivables, which is not particularly predictable.
Choice "c" is incorrect. Accounts receivable is affected by payments received from customers, which is not particularly predictable.
Choice "a" is incorrect. Accounts payable is affected by payments made at the discretion of the client, which may not be particularly predictable.