You need to import the legacy Excel data into Dataverse. The data contains duplicates and needs some cleaning. You decide to use Excel for data preparation and ensure that import columns have correct names and contain values in the proper Dataverse data type. 
What recommended tool should you use for this import?

Answer options:

A.Data Import Wizard
B.Dataflows
C.Power Query
D.Data template
E.Azure Data Factory

Correct Answer: D 
Dataverse provides several tools to import and export data. They include Data Import Wizard, Power Query, Power Automate, Dataflows, and others. 
Suppose you need to import your data using Excel and ensure that import columns have correct names and contain values in proper Dataverse data type. Microsoft recommends using the Data template to prepare import data. 
A Date Template is an Excel file with predefined fields for the table you want to import. 
You can download the template by following the Power Apps Advanced settings/Settings/Data Management (Number 1) path to the "Templates for Data Import" menu item (Number 2). After you click on this item, on the new screen (Number 3): 

The Data template is an Excel spreadsheet that provides the column names and information about their data types and validations, such as the maximum length for the text entries or the Whole number`s value range or required Lookup field. 

After filling in this template with cleaned data, you can import the file into the Dataverse using Excel as a data source. 
All other options are incorrect because they are tools for data import of already prepared data, and some of them are not suitable for an Excel import. 
For more information about Power Platform data import, please visit the below URLs: 

https://docs.microsoft.com/en-us/powerapps/maker/data-platform/data-platform-import-export
https://docs.microsoft.com/en-us/power-platform/admin/download-template-data-import
https://docs.microsoft.com/en-us/learn/modules/project-test-process/3-migrate-data