What type of functionality does the REST API provide?

The REST API in Tableau provides the capability to automate Tableau Server management and integrate it with various applications. It allows developers to perform administrative tasks programmatically, such as creating users, managing groups, updating data sources, and performing other management operations without the need for manual intervention through the Tableau Server interface. This automation enhances efficiency and ensures that the Tableau environment can be managed consistently and reliably, especially when integrating with other systems or workflows.

While the other options describe functionalities that may seem relevant, they do not accurately capture the core purpose of the REST API. For instance, sending notifications for data refresh and generating backup files pertain to other aspects of Tableau Server operations, while providing real-time data analytics relates more to the dashboard and visualization capabilities rather than the management functionalities facilitated by the REST API. Thus, the correct identification of the REST API's primary function as enabling server management and integration makes option B the appropriate choice.