The auditor wants to determine that only the marketing manager has approved changes to the product price file. Which of the following audit procedures would provide the most persuasive evidence that only those price changes that have been properly authorized by the marketing manager have been made?

a. Use an integrated test facility (ITF) and submit product orders to the ITF. Compare the prices invoiced to the prices in the most recent catalog.

b. Use the SCARF audit technique to create a listing of all customer orders exceeding a specified dollar limit, and print out the results for subsequent investigation.

c. Obtain a copy of all authorized price changes and manually trace to the current edition of the organization’s catalog.

d. Obtain a computerized log of all changes made to the price database. Take a random sarnple of changes and trace to a signed list of changes authorized by the marketing manager.