Nicolas Hill, CFE, Has Been Hired to Look into Suspicious

Nicolas Hill, CFE, has been hired to look into suspicious activity at Mason & Jefferson, LLC. The company's controller has reason to believe that the company has fallen victim to a shell company scheme. As part of his investigation, Nicolas should do which of the following?

A) Match the vendor master file to the accounts receivable file
B) Review payments with little or no sequence between invoice numbers
C) Extract all employees without a social security number
D) All of the above