Answer:
b. involves asking a respondent a set of semistructured, probing questions in a face-to-face setting.
Step-by-step explanation:
This is the best description of an in-depth interview. This kind of interview, as the name states, is meant to be "deep." Therefore, it presents probing questions. Moreover, it also requires the interview to be carried out in a face-to-face setting, as this creates a sense of intimacy, and is likely to encourage the respondent to be honest and open.