Answer:
the broker-dealer must notify the customer of the additional charges prior to executing the transaction
Step-by-step explanation:
In such a scenario, the statement that would be completely true is that the broker-dealer must notify the customer of the additional charges prior to executing the transaction. Since the broker is acting on behalf of the customer, then the customer needs to be notified beforehand in order for him/her to be able to analyze and decide whether or not they still want to go ahead with the transaction.