Answer:
Setting: is the physical location of a story which can greatly shape the stories mood.
Theme: is a contributing factor to the mood and the mood is a contributing factor to the theme, both elements reinforce each other.
Word Choice: your word choice is a key point in setting a mood. Like if you use discouraging words the mood will be discouraging, if you use sad word the mood will be depressed or sad.
Hope this helps:)