Hanover Research Business Development Associate interview questions

Interviewed with manager of the BDA theam, then two other Senior BDAs who had been in role for years. Typical interview questions and asked what I knew about their "product"/research. had a few personal questions

Easy questions but the interview process was extremely lengthy. The first interview was a screening call with an HR member, the second one was with two senior members (about 1.5 hrs), and the last one was with two BDAs (about 45 mins). They also make you take an assessment that took about 30 minutes. Most people showed up in a regular t-shirt on the video call, which put me off since you wouldn't do that for a normal interview - a bit unprofessional.