Internship Final Round - Deal/Industry/Stock Pitch

This week, I am going into my final round interview for an IB Internship with a boutique U.S. firm. In the previous round my interviewers asked me which team I would like to work on should I be successful, and I answered the PU&I team because I had spoken with a number of people from the team and they came across very friendly/ helpful.

My next interview is with a VP and ED from the PU&I team, but I don't know much about PU&I aside from the basics of a rate regulated utility. Should I be looking to build my deal talk/ industry talk and stock pitch around PU&I given my declared interest and the specialty of the interviewers? It is worth mentioning the firm does not specialize in PU&I so it's not like they are only looking for recruits with PU&I knowledge that perhaps an M&M firm may look for.

I know this may seem like a stupid question, but I've heard mixed answers "don't gear your answers towards an industry you don't know" and "well if you said your interested prove it".

Thanks for your help in advance!