Why can I not set the source question for a roster

I have 3 items…

The first is a list question for respondents to list all household members.

The second question is a multi-select question which is linked to the first question so that the options are the household members.

The third item is a roster. I would like to set this roster’s source question as the second question, so I select the source as a multi-select question but, when I go to select the source question, it is not there.

Why is this?

Dear @rakesh ,

Please take a look here.

Read this 3-year old thread for explanations to your case: