Answer:
D) The broker-dealer must be registered in State B in order to contact the client while she is in medical school in State B
Step-by-step explanation:
Since the client will live in state B for an extended period of time, at least 4 years if she completes medical school, the broker-dealer must be registered in state B if he wishes to continue doing business with her.
If the client would have only gone to state B for a few months, then the broker could have still worked with her without registering in state B since the client could be considered on a vacation trip.