A CPA issued an unqualified opinion on the financial statements of a company that sold common stock in a public offering subject to the Securities Act of 1933. Based on a misstatement in the financial statements, the CPA is being sued by an investor who purchased shares of this public offering. Which of the following represents a viable defense?

The audit work was performed with due diligence.

The CPA detected the misstatement after the audit report date.

The investor did not rely upon the financial statement.

The investor has not proven CPA negligence.