The red flags that most likely triggered the referral are:
B: Several cash deposits along the country's border that are quickly withdrawn by third parties. C. Several lodging and food payments made on the same day at unusual hours for a business.
Red flag B suggests possible structuring activity, where individuals are trying to avoid currency transaction reporting requirements by depositing and withdrawing cash in amounts below the reporting threshold. This activity is often associated with money laundering and could indicate human trafficking activity.
Red flag C suggests unusual activity that may be indicative of human trafficking, such as lodging and food payments made at unusual hours or in unusual patterns. This type of activity could indicate that the business is being used as a front for human trafficking or that the individuals involved in the trafficking are using the business to facilitate their activities.