I want to create a multiple choice question where one of the options is free text entry (e.g. Other: __________). However, I am importing my survey from a .txt file. How do I write this command into the .txt file?

It currently looks like this:

[[Question:MC:SingleAnswer:Vertical]]

[[ID:Gender]]

What gender do you identify as?

[[Choices]]
Female
Male
Other <---- this is where I want text entry