You could do the same as outlined in the image below:
In the survey tab of your xlsform:

In the choices tab of your xlsform:

Data entry screen as seen in Enketo:
Reference xlsform:
Auto Select.xls (29.5 KB)
Note: You could also use the ready_only if you wish to have the response for Q2 locked as shown in the image below:

Reference xlsform:
Auto Select.xls (29.5 KB)

