For one you can put a tree branch because in the book they talk about a tree
The Tempest opens in the midst of a storm, as a ship containing the king of Naples and his party struggles to stay afloat. On land, Prospero and his daughter, Miranda, watch the storm envelop the ship. Prospero has created the storm with magic, and he explains that his enemies are on board the ship.
What? Am I supposed to do something
I think the correct answer from the choices listed above is the last option. The best definition of a unity in an artwork would be the feeling of oneness that occurs when all the parts of a design fit together well. Hope this answers the question. Have a nice day.