First of all, congrats on all of the schools you were accepted to! Since you think you might want to pursue a career in development or public relations, you might want to consider which schools offer courses/opportunities for you to explore these areas. Of course there are exceptions, but arts management programs will usually be more business focused than museum studies programs.
From my somewhat limited experience, none of the development or public relations staff that I have worked with received a degree in museum studies. I'm not saying that it is impossible to be successful in those areas with that degree, but most museum studies programs are curatorial/education/collections management focused.
I would suggest really thinking about your career objectives. If you are unsure, you might want to go to the museum studies route (or MBA combo), which would have a more generalized curriculum.
This blog post might help you out! http://museumblogging.com/2011/11/23/how-to-pick-a-good-graduate-program/
Good luck!