The Black Market Peso Exchange (BMPE) is a trade-based money laundering technique commonly used by narcotics traffickers based in Colombia and Mexico. The central feature is the use of a money trader to ensure that the revenue from drug sales in the U.S. doesn't actually cross any borders. Instead, those dollars are used to purchase any number of legitimate commodities from unsuspecting businesses on behalf of legitimate South American businesspersons, whose legitimate imports are used to obtain pesos for the drug cartels12.
The BMPE involves six distinct steps:
* Obtaining criminal proceeds: The drug cartels sell drugs for dollars in the U.S.
* Involvement of intermediary services: The drug cartels sell the dollars to black market peso exchangers in Colombia at a discounted rate.
* Identification of complicit companies: The black market peso exchangers identify exporting companies in the U.S. and importing companies in South America that are willing to participate in the scheme.
* Placement of funds: The black market peso exchangers deposit the dollars into U.S. bank accounts or use money service businesses or other methods to transfer the funds.
* Layering of funds: The black market peso exchangers use the funds to purchase monetary instruments such as checks, money orders, or wire transfers, or to pay for the goods ordered by the South American importers.
* Integration of funds: The South American importers receive the goods or the monetary instruments and use them to pay for their imports or to sell them for pesos in the local market.
References:
* 1: Black Market Peso Exchange in Money Laundering - Financial Crime Academy
* 2: Overview - FinCEN.gov

This involves breaking down large amounts of cash into smaller transactions that are below the reporting threshold of $10,000 in the United States, in order to avoid detection and reporting by the financial institution.
Structuring is a red flag for money laundering and should be reported to the authorities as a suspicious activity.
The other options are not necessarily indicative of money laundering, as they could have legitimate explanations. For example, the customers may have a family or business connection to the same recipient in Country B, or they may have a regular need to send money three times a week.
References:
* ACAMS CAMS Certification Video Training Course, Chapter 2: Money Laundering Risks and Methods, Section 2.2: Common Money Laundering Techniques
* Exam CAMS: Certified Anti-Money Laundering Specialist (the 6th edition), Question 91
* CAMS Certification Package - 6th Edition, Study Guide, Chapter 2: Money Laundering Risks and Methods, Page 38

Explanation
https://www.fdic.gov/regulations/laws/rules/5000-4800.html
When analyzing individual transactions, examiners will review an appraisal or evaluation to determine whether the methods, assumptions, and value conclusions are reasonable. Examiners also will determine whether the appraisal or evaluation complies with the Agencies' appraisal regulations and is consistent with supervisory guidance as well as the institution's policies. Examiners will review the steps taken by an institution to ensure that the persons who perform the institution's appraisals and evaluations are qualified, competent, and are not subject to conflicts of interest.