When adding an activity to a data pipeline that supports Power Query M formula language, which type of activity should be added?

The correct choice, which is to add a Dataflow activity, is based on the integration and support for the Power Query M formula language in data transformation processes. Dataflows are specifically designed to ingest, cleanse, and transform data using the capabilities of Power Query. They allow users to leverage the M language for building complex data transformations and workflows.

Dataflows provide a robust environment for ETL (Extract, Transform, Load) operations, enabling users to create reusable transformation logic that can be shared across multiple data pipelines. By selecting a Dataflow activity, you ensure that the transformations align with the Power Query capabilities, making it easier to handle various data sources and perform advanced data manipulation tasks.

Other types of activities like Notebooks, Scripts, and Copy Data are not specifically tailored for the Power Query M language. Notebooks can be used for executing code in an interactive environment, but they are more suited for exploratory data analysis than for structured data transformations as provided by Dataflows. Scripts can also perform data manipulation tasks, but they do not inherently support the M language. Copy Data activities are focused on the simple movement of data from one place to another without transformation capabilities. Therefore, adding a Dataflow activity is the most appropriate choice to fully take advantage of Power Query