While conducting an audit of a third party's Web-based payment processor, an internal auditor discovers that a programming error allows customers to create multiple accounts for a single mailing address. Management agrees to correct the program and notify customers with multiple accounts that the accounts will be consolidated. Which of the following actions should the auditor take?

1. Schedule a follow-up review to verify that the program was corrected and the accounts were consolidated.

2. Evaluate the adequacy and effectiveness of the corrective action proposed by management.

3. Amend the scope of the subsequent audit to verify that the program was corrected and that accounts were consolidated.

4. Submit management's plan of action to the external auditors for additional review.