How to make Interesting field into a selected field?

How to make Interesting field into a selected field?
A . Click field in field sidebar -> click YES on the pop-up dialog on upper right side -> check now field should be visible in the list of selected fields.
B . Not possible.
C . Only CLI changes will enable it.
D . Click Settings -> Find field option -> Drop down select field -> enable selected field -> check now field should be visible in the list of selected fields.

Answer: A