Creating a Fillable Form

Hello Adobe Community,

My research seems to be failing me. It's likely the search criteria I'm entering, but I'm looking to create a fillable form for workforce management tasks. In essence, I'm using JavaScript to create Custom Calculation Scripts. 

I have a dropdown which has several options for department. If a user populating the form selects one of five options (total ~15 options), a separate text field and checkbox is supposed to appear. I can figure it out if I configure the script to look for a single dropdown selection, but I'd like to configure it so if a user chooses any of those five options, the text field will be displayed. 

Any syntax or KB article you can throw my way would be super useful. Anything I've come across doesn't quite meet my requirement.