How can an Einstein Analytics consultant derive those KPIs from those datasets?

A company wants to build a webpage that displays KPIs that can be derived from values in datasets stored in Einstein Analytics.

How can an Einstein Analytics consultant derive those KPIs from those datasets?
A . Use the Analytics External Data API and leverage the "query" resource.
B. Export the dataset as an XLS file and use the Einstein Analytics Connector for Excel.
C. Use the Analytics REST API and leverage the -query" resource.
D. Export the dataset as a CSV file and load it to an external database.

Answer: A