Just guessing: business professional. I would wear a skirt-suit, with or without the jacket. Two reasons: one, I find it is better to be over dressed than underdressed, two, dressing nicely gives a kind of confidence. In this case that confidence can easily be “I belong here, I am just as important as anyone else here”. Edited to add: I would bring the jacket, but use it as a way to dress up or down depending on the crowd.