Hi @Charly,
Welcome to the community! You could do the same as outlined below.
If you are using the form builder user interface:
If you are using the xlsform:
In the survey tab of your xlsform:
In the choices tab of your xlsform:
Data entry screen as seen in Enketo:
Reference xlsform:
Minimal.xlsx (10.9 KB)
Have a great day!