Select_one in repeat group

[ARIF_AZAD_KHAN]

Get the answer here

Duplicate value in repeat group question

Hiii, I have developed an survey app using odk , Now the issue is I have created one repeat-group question , this group have a question where i am asking for multiple response in it. Now, I want when the next time repeat comes previously taken option could not be chosen again. example: Q which service do use want to use (a, b, c, d, e) Now if , a is selected next time a should not be selected again..) It would be very helpful if anybody provide me support for this. Thanks in Advance