Note: This question is a part of a series of questions that present the same scenario. For your convenience, the scenario is repeated in each question. Each question presents a different goal and answer choices, but the text of the scenario is exactly the same in each question in this series.
Start of repeated scenario
You have a Microsoft SQL Server database that has the tables shown in the Database Diagram exhibit.
(Click the Exhibit.)

You plan to develop a Power BI model as shown in the Power BI Model exhibit. (Click the Exhibit).

You plan to use Power BI to import data from 2013 to 2015.
Product Subcategory [Subcategory] contains NULL values.
End of repeated scenario.
You implement the Power BI model.
You need to add a new column to the Product Subcategory table that uses the following formula.
=if [Subcategory] =null then "NA" else [Subcategory]
Which command should you use in Query Editor?