Which of the following is not a required campaign property?

In Adobe Campaign Classic, campaign properties are essential for defining how a campaign is structured and executed. Among these properties, the name, type, and start date are all required to set up a campaign properly.

The name of the campaign is crucial as it serves as the primary identifier for users to recognize the campaign within the system. The type defines the nature of the campaign, such as whether it is a promotional campaign or a transactional one, which influences how the campaign is processed and how it interacts with different components of the platform. The start date is required as it indicates when the campaign is scheduled to begin, which is critical for planning and execution.

On the other hand, the nature of the campaign—though useful for providing additional context or classification—is not mandatory for the campaign to function. It serves as an optional descriptor that can help categorize or provide insights into the campaign's focus or objective, but lacking this information does not impede the overall setup or execution of the campaign. Thus, it is not classified as a required property, allowing users the flexibility to define campaigns without it.