A short story has clear plot development, while a poem does not.
This is the best answer choice. One of the traits of a short story is clear plot development. A short story has a single plot line with a clear central conflict. A short story's characters do not have to be complex. In fact, the singular plot line can make it difficult to have more than one complex character. Both short stories and poems can use sensory language and develop a larger theme. It should be noted that narrative poems usually have clear plot development. However, this is only one type of poem.
