The choice that best states one purpose of an interview is to ask well-researched questions.
The purpose of an interview is two-fold: in case of a job interview, for example, both parties listen intently and speak accurately so as to get an insight into the person's competencies and the employer's objectives. Parties attending the interview could also exchange information regarding a given topic. To do so, accurate, comprehensive, well-reasoned questiones are posed.
Thoreau's actions reveal that he believes the society to be corrupt. That is why life in the woods is the best possible option for any human being. Reconnecting with nature and abandoning cities.