In the audit of accounts receivable at XYZ company (the client), the gross amount (i.e. not including Allowance for doubtful debt) presented on the financial statement is $700,000 which includes customer A ($300,000) and company B ($400,000). The balance of Allowance for doubtful debt account is zero. You are the auditor and you are asked to check the accounts receivable account.

Required: a. You are instructed by your audit manager that you should send a confirmation letter to each customer A and B requesting them to confirm the amount they owed to your client. State the type of audit procedure you are asked to take?