Which of the following is a necessary action for a valid listing agreement?

For a valid listing agreement, specifying the duration of the agreement is essential. This detail establishes how long the real estate agent will have the authority to represent the seller in the sale of the property. It provides a clear timeframe for both parties, which is crucial in managing expectations and ensuring that the agreement is enforceable.

The duration is also important because it allows the seller to understand how long they are committing to work with the agent and gives the agent a defined period to market the property and attempt to secure a sale. Without this specification, the agreement may lack clarity and could lead to disputes about the representation period.

The other options, though relevant in different contexts, do not hold the same necessity for a valid listing agreement. For instance, while informing agents of certain aspects of the property or the seller's wishes is prudent, it is not a formal requirement for the agreement to hold validity. Disclosure of property condition is crucial for ethical practice and may be required later, but is not a prerequisite for the listing agreement itself. Lastly, title deed transfer is part of the selling process, not a condition for creating a listing agreement. Thus, focusing on the agreement’s duration is the key necessity for its validity.