What would be the main limitations? What are the ethical issues involved?

Option #1: Qualitative Research
As a researcher, it’s in your interest to develop an in-depth perspective of the daily living of inmates in prisons. To execute this investigation, you need to conduct qualitative interviews of inmates.

What could be the disadvantages advantages of phone or in-person interviews?
Would a non-structured or structured interview be most favorable?
Is this study viable?
What would be the main limitations?
What are the ethical issues involved?
Would you be able to establish empathy with the inmates to reach quality data?
Write a paper, describing your plan for qualitative research, along with your responses to the above questions.