Answer – B 

According to Interviewing.com, 40 minutes is the average length of an interview.

We recommend scheduling at least 60 minutes for each office interview.  Build rapport during the first 5-10 minutes by providing a company overview and reviewing key job accountabilities.  During the next 40 minutes, ask behavioral based questions that are relevant to the key accountabilities.  The remainder of the time can be used for candidate questions and wrap up.  Strive to end the interview on a positive note, yet provide realistic expectations of next steps in the hiring process if they are a viable candidate.

Review our Safari Guide for a simple way to structure a 60 minute office interview.