You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: ANATOMY 
Clue: Organ whose workings were the subject of a 1604 work by Johannes Kepler
the eye

Category: BUSINESS BIGGIES 
Clue: Founded in 1898 when several cracker companies merged, in 2000 it passed from one tobacco company to another
nabisco

Category: FICTIONAL CHARACTERS 
Clue: Title hero whose boarding school's motto is "Draco Dormiens Nunquam Titillandus", "Never Tickle A Sleeping Dragon"

harry potter