The "bunny" definitions of competition categories might help guide your category choice:
a. Action/Adventure: Secret Agent James Bunny, code name '7.23Cottontail', strives to overcome the machinations of the evil doctor who wants to take over the world. His cousin, Indyana Bunnie, swings over a waterfall, clutching the Stone of Persistence in his grimy little paw while crazed bunny-eating foxes try to hit him with rocks.
b. Contemporary fiction (Formerly Mainstream fiction): A bunny takes a cross-country trip and meets interesting characters along the way. He is not magical nor newly un-zombied, has not escaped from an institution for the criminally inclined, is not from the past nor plans to travel to the future, and does not boff excessively with either female bunnies or male bunnies...or beasts of any ilk.
c. Erotica: A bunny boffs with him/herself or one or more others, with no expectation other than sexual exploration and pleasure.
d. Fantasy: A magical bunny, from the world of Garn, pits his skills against an evil wizard lizard.
e. Historical: A bunny is a soldier in the Civil War, lives in Regency England, or rides the buffalo range...or all three.
f. Horror: A bunny comes back from the dead to take revenge on the foxes who ate him, BBQing them over hot coals one at a time and leaving their bones for their friends to find.
g. Mystery: A hard-boiled detective bunny solves a crime and locks away the mad squirrel scientist. A librarian-amateur sleuth bunny solves a surprising number of murders in her small town. A private investigator bunny, disillusioned with the world, is asked to find a missing lady bunny. In the end they discover the truth behind nefarious plots, saving the day with (often) heroic fervor.
h. Paranormal: A wicked time-traveling ghost bunny from Devonshire haunts the vampire-rat residents who are stalking the beautiful werebears. A psychic bunny helps the police find the Mayor's missing baby frogs. Depending on how much the psychic powers play in the story, the above could be a mystery or a suspense/thriller, i.e. is it predominantly a detective story or is the bunny in extreme danger from her investigation or is it more focused on the paranormal aspect of the bunny's psychic ability?
i. Science Fiction: Space bunnies with really cool gadgets travel to a newly discovered planet, only to find danger from alien bunny-munching monsters.
j. Spiritual: A bunny seeks to understand the invisible, spiritual nature of life, transcending the physical, material plane. Stories entered in this category can be from any faith tradition.
k. Suspense/Thriller: Your heroine uncovers the truth behind the little bunny-down-the-lane, who is really the axe-wielding murderer terrorizing a small Southern town.
l. Romance works may be any of the genres listed above, but must conform to the romance genre convention, that is, your bunnies find true love; they may be chaste (spiritual/inspirational), boff behind closed doors (sweet), boff energetically (more spicy), or boff themselves silly in interesting ways (erotic). Some erotic romances involve multiple lovers...but as long as they find true love, it's a romance.