32 Bars?!

"Please sing 16 to 32 bars of a song."

Um...okay.  How am I supposed to pick the perfect song to show off my voice, when I only have 16 to 32 bars to do so?  I mean, seriously...  My sister said to pick one that shows off my voice the best.  My question:  "Which voice?"  Another pitfall of being a mezzo.  And being healthy at the moment.  I have my low range and my high range right now.  Do I want to show off my high operatic or my low belt?  What about my rich middle range?  Can I find a song that, within 32 bars, shows off both?!  And doesn't hover too much around my break?

This is a VERY IMPORTANT audition, because it's season auditions for a theatre that is looking at changing a philosophy about a few things.  My audition songs for the show I plan on doing this summer (with another company) are set, but this other audition is freaking me out!  I DON'T KNOW WHAT TO SING!!!!!