D. they generally end with something that surprises readers
Most short stories were made to entertain so they usually end with a twist and have readers hooks.
But some stories, teach an important lesson and they include something totally unexpected in order to get the reader thinking.
For example, one short story I've read (I can't remember the title) had two friends who just enjoy fishing together, and one day they're out fishing and in the end they both are killed. You weren't expecting that at the end but, it made you think about how the story relates to things that happen today.