If you want to screw their analytics, choose Other and write something random in it.

All other fields go straight into meaningful numbers and it's easy to automatically detect an empty Other and assign it to a generic category, but random text in Other has to be read and understood by a human to categorise (because you can't yet automate the detection of randomness or meaningless, whilst you can easilly enough automate things like detection of swear words to classify it into "pissed off user").

On the other hand an empty Other is the simplest fastest way to just go over an unecessary barrier like that if you just want to get done with it and aren't trying to make a point.