Which Analytics 360 feature would you use to create a new data set by combining data from multi-source properties to get a broad view of your business across brands, products, or regions?

Roll-up properties is correct because in Google Analytics 360, roll-up properties allow you to aggregate data from multiple source properties into a single property, enabling a unified view of user behavior and performance across different brands, products, or regions. This helps businesses analyze cross-property trends and metrics in one place, whereas subproperties, data streams, or organizations serve different purposes like structuring accounts or collecting raw data from individual sources.