Maybe I don't understand the options properly because I don't have a North American accent, but I pronounce it pia-nist (or pia-nuhst), with no emphasise on an "an" sound.
I usually pronounce it as either pee-ah-nist or pee-ann-ist, so I chose the first option. I've heard a lot of variations but those tend to be the most common from my experience.
I gotta admit, I don't fully understand the pronunciations on the poll, but I pronounce it pee-an-ist with "pee" said quite quickly if that makes sense? So I dunno if that means I pronounce it pean-ist?