Final answer:
Robert should sign a Buyer Representation Agreement with the buyer to exclusively represent them in a property transaction, establishing a dedicated relationship between the buyer and Robert as the agent.
Step-by-step explanation:
If Robert is looking to exclusively represent a buyer in a transaction, the document he should sign with the buyer is a Buyer Representation Agreement. This agreement establishes an exclusive relationship between the buyer and the real estate agent or broker, ensuring that the agent represents the interests of the buyer exclusively. An Open Listing allows multiple agents to work on selling the property, with only the selling agent being compensated. A Listing Contract is typically an agreement between a seller and an agent, and an Exclusive Agency Agreement is also for sellers, allowing them to retain the right to sell the property themselves without paying the agent a commission.