Final answer:
In a bankruptcy proceeding, the hiring of a fraud investigator usually requires the approval of the bankruptcy court unless the fees are paid directly by an individual creditor or shareholder, in which case court approval may not be necessary.
Step-by-step explanation:
The student's question relates to bankruptcy law and specifically the conditions under which the retention of a fraud investigator in a bankruptcy proceeding must be approved by the bankruptcy judge. According to U.S. bankruptcy law, generally, the hiring of professionals such as fraud investigators that will be paid out of the bankruptcy estate requires the approval of the bankruptcy court. This is to ensure that the professionals are qualified, that their services are necessary, and that the fees charged are reasonable.
However, there are exceptions to this rule. If an individual creditor or shareholder were to pay for the services of a fraud investigator directly and not out of the debtor's estate, then the bankruptcy court's approval might not be necessary. Between the options provided (a) the debtor's estate pays the investigator, (b) the trustee pays the investigator, (c) the creditors committee pays the investigator, and (d) an individual creditor or shareholder pays the investigator, the correct answer is: d) an individual creditor or shareholder pays the investigator.