Final answer:
After the transaction closes, the broker has the obligation to account for any money or property relating to the transaction. This includes proper handling and documentation post-closing. Other duties listed are typically addressed during the transaction.
Step-by-step explanation:
The question relates to the obligations of a real estate broker after a transaction has closed. Among the choices provided, the correct answer is (c) Account for any money or property relating to the transaction. This means that the broker is responsible for ensuring that all funds, documents, and any other property involved in the transaction are properly handled and accounted for, even after the closing of the deal. The other options - disclosure of the brokerage relationship, disclosure of future vicarious liability, and disclosure of any substantial misrepresentations relating to the transaction - are responsibilities that generally need to be fulfilled during the transaction process, not after its completion.