One of the key elements emphasized in AU-C 240 is for an auditor to have heightened professional skepticism in conducting an audit. The AICPA's Audit Risk Alert identifies a list of "circumstances and observations" that should catch the attention of the auditor. That list includes which one of the following: a. a company that has a culture of humility b. a strong audit committee and board governance c. an overly loyal management team d. an overly centralized control over the financial reporting process