In One of the Cases in the Textbook, Swainler's Technology

In one of the cases in the textbook, Swainler's Technology discovered that someone had stolen 1,400 hard drives from its computer warehouse. In order to collect on its theft insurance policy, the company had to show that the theft was an outside job. Before the insurance company paid Swainler's claim, it hired an independent investigator, who ultimately found that the hard drives were stolen and sold by Swainler's marketing manager, Frederic Boucher. How did the investigator identify Boucher's involvement?

A) Boucher's ex-wife found out and contacted Swainler's board of directors.
B) A former employee of Swainler's went to work for a competitor and told his manager about Boucher's involvement.
C) The investigator found telephone calls made by Boucher to a warehouse where some of the stolen drives had been traced.
D) Investigators found a large cash deposit in Boucher's bank account around the time that the drives went missing.