What Should a Field Researcher Do When Conducting Interviews in a Field

What should a field researcher do when conducting interviews in a field site?

A) Intersperse questions into informal conversations and tailor questions to specific people being interviewed.
B) Follow the exact wording of questions and do not improvise.
C) Never reveal any personal information and him/herself to anyone being interviewed.
D) Always ask the same questions in the same order to each person in a field site.
E) none of the above