Final answer:
Self-administered surveys are the mode in which participants complete the questionnaire on their own without an interviewer, beneficial for sensitive topics.
Step-by-step explanation:
The survey mode that is different from other methods in that there is no agent—human or computer—administering the interview is C) self-administered surveys. This mode of survey allows participants to complete the questionnaire on their own without direct interaction with an interviewer, which could be beneficial when dealing with sensitive or highly personal issues. Common distributions of self-administered surveys include paper questionnaires, online surveys, and e-mails.