Which sentence fails to use correct parallel structure? a) the dentist told the classroom of kindergarteners that they each needed to floss, brush, and rinse daily. b) the boat was indeed expensive, but with it, the family could ski, fish, or just swim far out on the lake. c) i'm not sure what's wrong with my computer--it's starting to beep, it's getting slower, and it's getting really warm. d) do not attempt to do these stunts at home unless you are a professional, you have experience biking, and the paramedics are not far away.