What is a project operator in KQL?

Answer options:

A.Project operator add, rename or remove columns in the result set.
B.Project operator filter out a table to the subset of rows.
C.Project operator creates précised columns and add them to the result set.
D.None of the above

Correct Answer: A
Option A is correct. Project operators control what columns to include, add, remove or rename in the result set of a statement.
Option B is incorrect. The where operator filters a table to the subset of rows that satisfy a predicate.
Option C is incorrect. Extend operators can`t use aggregate functions.
Option D is incorrect.
Reference: 

https://docs.microsoft.com/en-us/azure/data-explorer/kusto/query/projectoperator