How to auto-populate a certain option from a dropdown menu when you type on a certain field?

Hi!

I'm fairly new to using and making forms on Acrobat Reader. I was recently tasked to do a pdf form for my job and I have no experience with javascripts and codes. My boss wanted this certain option to appear when typed on the circled field on the picture. I tried looking for answers on Google and I didn't really understand how to do it. Can someone help me?