An auditor's independence would not be considered impaired if the auditor had done which of the following? ( ) A. Owned common stock of the audit client but sold it before the company became a client B. Sold short the common stock of an audit client while working on the audit engagement C. Served as the company's treasurer for six months during the year covered by the audit but resigned before the company became a client D. Performed the bookkeeping and financial statement preparation for the company, which had no accounting personnel, and the president had no understanding of accounting principles