Final answer:
The appropriate alternative procedure to gain assurance regarding the customers' accounts balances when using positive confirmations and not receiving responses to initial or second requests is the b) examination of subsequent cash receipts.
Step-by-step explanation:
The appropriate alternative procedure for Shawn Hiwa to gain assurance regarding the customers' accounts balances when using positive confirmations and not receiving responses to his initial or second requests would be an examination of subsequent cash receipts. This involves examining the cash receipts received from customers after the confirmation request to see if they match the accounts receivable balances. If there are cash receipts corresponding to the unresponsive customers, it provides evidence that the account balances are valid. This procedure is useful in situations where confirmations are not received or if the confirmation results are unreliable.