A CPA prepares income tax returns for a client. After the client signs and mails the returns, the CPA discovers an error. According to Treasury Circular 230, the CPA must
A. Promptly resign from the engagement and cooperate with the successor accountant.
B. Prepare an amended return within 30 days of the discovery of the error.
C. Promptly advise the client of the error.
D. Document the error in the work papers.
Answer: C