When must you state the model year of a motor vehicle?

Answer: A — When advertising it

When advertising a motor vehicle, it is important to state the model year as it provides important information about the vehicle and can affect the buyer's decision. It is not necessary to state the model year when negotiating the price or completing the sale as these details can be discussed during the transaction. Additionally, while it is important to display the model year when the vehicle is on the lot, it is not the only time when it must be stated. Therefore, the correct answer is A, as it specifies a specific scenario in which the model year must be mentioned.