Which of the Following Is a Procedure Used in an Audit

Which of the following is a procedure used in an audit where there is a heightened risk of fraud related to accounts payable and other related expense accounts?

A) Send blank confirmations to vendors that ask them information about all outstanding invoices,payment terms,payment histories,and so forth.
B) Scan journals for unusual or large year-end transactions and adjustments.
C) Obtain and examine documentation for payments of invoices that are for amounts just under the limit that typically requires some level of approval.
D) All the above.