How should the branch manager respond to this activity?

The branch manager notices that a number of customers come in weekly and always use the same teller to process their deposits. The manager notices that the customers and the teller, who are from the same ethnic group, are speaking in a foreign language and every once in a while the customers from local ethnic restaurants will bring the teller lunch. The commercial customers that visit the teller generally deposit the same amount of cash each time they come in.

How should the branch manager respond to this activity?
A . Transfer the teller to another branch
B. Conduct further investigation before taking any other action
C. Encourage the teller to bring in more business from the ethnic community
D. Suggest to the teller to send the customers to other tellers to avoid the opportunity for collusion

Answer: B