According to the CAMS Study Guide, page 173, "If an independent investigation provides grounds to interview the employee, the employee can be interviewed and, if necessary, terminated, but not advised that he or she is under investigation by law enforcement." This is because informing the employee of the law enforcement investigation could compromise the integrity of the case and potentially expose the institution to legal liability. Therefore, option B is the correct answer.
References:
* CAMS Study Guide, page 1731
* CAMS Exam Questions and Free Practice Test, Question 2872

Under the Egmont Group Principles, information exchange among financial intelligence units (FIUs) should be conducted freely, spontaneously, and upon request, on the basis of reciprocity. This means that FIUs should be willing to share information without the expectation of reciprocity on how the information will be used. The goal is to facilitate the cooperation and exchange of information among FIUs to combat money laundering, terrorist financing, and other financial crimes.

Explanation/Reference: http://fraudaid.com/Dictionary-of-Financial-Scam-Terms/black_market_peso_exchange.htm

The anti-money laundering officer (AML officer) is responsible for overseeing the implementation and effectiveness of the anti-money laundering (AML) program of a financial institution. The AML officer should have sufficient authority, independence, and access to resources to perform this role. Reporting to the Sales Director may compromise the independence and objectivity of the AML officer, as the Sales Director may have conflicting interests or incentives that could influence the AML officer's decisions or actions. The AML officer should report to a senior management level that is independent of business functions and has direct access to the board of directors or a relevant committee. This would ensure that the AML officer can communicate any AML issues or concerns to the board without any interference or undue influence from the business functions.
References: = Some of the references that support this answer are:
ACAMS Study Guide for the CAMS Certification Examination, Chapter 2, Section 2.2.1, page 41: "The AML officer should report to a senior management level that is independent of the business line and has direct access to the board of directors or a relevant committee." Money Laundering Reporting Officer: The Role Of MLRO, Section "Role Of Money Laundering Reporting Officer": "The MLRO should have independent monitoring and should be able to connect directly with people who make business decisions, such as senior management or the board of directors." Money Laundering Reporting Officer (MLRO)? | Dow Jones, Section "What is a Money Laundering Reporting Officer (MLRO)?": "A Money Laundering Reporting Officer (MLRO) is tasked with overseeing a firm's compliance with the Financial Conduct Authority's (FCA) rules on money laundering. ... The MLRO should have sufficient authority and independence within the firm to carry out their responsibilities effectively."