Question: ABC Company has 100 shares of IBM stock that it holds as an investment. The stock was purchased three years ago and has been in the client's safe deposit box along with other investment securities. During an inspection of securities held by the client, the auditor noted the 100 shares of IBM stock had a different CUSIP number than the number listed when purchased and the number verified during the previous audit. Which of the following would be the auditor's main concern about this discovery?
a. The certificates in the safe deposit box were forgeries.
b. There had been unauthorized buying and selling of investment securities.
c. The securities may be misclassified on the balance sheet.
d. ABC Company no longer owns the securities.