Answer:
Assessing the allowance for uncollectible accounts for reasonableness.
Explanation:
Assessing the allowance for uncollectible accounts for reasonableness give the most assurance concerning the valuation assertion about accounts receivable as The term uncollectible accounts receivable is used to describe the portion of credit sales in accounts receivable the company does not expect to collect from a customer.
Uncollectible accounts is used in the valuation of accounts receivable, which appears on a company's balance sheet.
