Which sentence has an error in parallel structure? a) charlotte didn't know which habit she found the most annoying: smacking gum, tapping pencils, sending text messages, or sleeping in class. b) the principal could never understand why teachers were late, failed to turn in their lesson plans, and yet still complained incessantly all day long. c) the teacher assigned an essay in which students needed to have a strong thesis, to create a clear structure, and they needed to make a logically progressive argument. d) each day at work at the ice cream shop, ben needed to check the inventory of ice cream, insure that all the workers showed up on time, and modify the menu board's offerings.