noun
respondent
rih-SPAHN-dunt/rɪˈspɑːndənt/
Someone who provides or must provide an answer.
Each respondent answers the survey questions without giving a name.

Etymology
“Pledging back” underlies the broader idea of answering. The participial form identifies the person doing the answering, whether to a lawsuit, survey, or other request.
In context
you could see if the respondent dropped out of the survey and stopped answering the question
More examples
- Most respondents say they prefer the new bus schedule.
- The interviewer asks the respondent to explain her answer.
- The respondent has thirty days to answer the petition.
Forms
Similar words
- interviewee
- Specifically answers an interviewer's questions, rather than any general inquiry.
- defendant
- Answers a lawsuit or criminal charge, not necessarily an appeal.