An auditor is evaluating the 'integrity' principle of the AICPA Code of Professional Conduct. Which of the following situations most clearly represents a violation of the integrity principle, rather than just the objectivity or due care principles?

The auditor inadvertently fails to detect a material error due to poor sampling technique.

The auditor accepts a gift from a client that is considered 'clearly insignificant'.

The auditor knowingly signs a report on financial statements that contain a material false statement.

The auditor subordinates their judgment to the client's preference on an accounting estimate.