Explanation
According to the Certified Anti-Money Laundering Specialist (the 6th edition), Section 2.2.5 Suspicious Activity Reporting (SAR) Requirements, a Suspicious Activity Report (SAR) filing is required when a financial institution is aware of, or suspects, a possible violation of law or regulation, or any other suspicious activity related to money laundering, terrorist financing, or other unlawful activity. In this case, Answer A would require a Suspicious Activity Report filing as the deposits are made on a daily basis without providing a legitimate purpose.
According to the Financial Crimes Enforcement Network's (FinCEN) guidance, one example of a suspicious transaction is "frequent deposits of cash or monetary instruments in amounts under $10,000 to the same account, or a pattern of such deposits, unless the financial institution has a reasonable explanation for the pattern." (CAMS Manual, 6th Edition, Page 209)

The most important consideration when deciding whether to recommend closing the account is the institution's anti-money laundering policy. This is because the policy should provide clear and consistent criteria for account closure decisions, based on the risk assessment, the nature and severity of the suspicious activity, the customer due diligence information, and the legal and regulatory obligations of the institution.
The policy should also ensure that the account closure process is independent, objective, and transparent, and that it does not compromise the confidentiality of the suspicious transaction report or the investigation.
References: =
* ACAMS Study Guide for the CAMS Certification Examination, 6th Edition, Chapter 5, Section 5.4.2, page 1971
* ACAMS CAMS Certification Video Training Course, Module 5, Lesson 5.4, video time 9:00-10:302
* ACAMS CAMS Certification Practice Exam, Question 145, page 2863

The activity of a teller distributing bank brochures to customers who regularly conduct cash transactions below reporting limits warrants further review. This is because the teller may be facilitating or encouraging structuring, which is a form of money laundering that involves breaking down large amounts of cash into smaller transactions to avoid detection or reporting requirements. Structuring is illegal and can expose the institution and the employee to civil or criminal penalties. The teller may also be acting as an agent or a recruiter for money launderers who use the bank's services to launder their illicit funds12.
References:
1: CAMS Certification Package - 6th Edition | ACAMS, Chapter 2: Money Laundering Risks and Methods, p. 28-29 2: FATF Report: Money Laundering through the Physical Transportation of Cash, October 2015, p. 23-24,
http://www.fatf-gafi.org/media/fatf/documents/reports/money-laundering-through-transportation-cash.pdf