The correct answer is tone. Imagery is using vivid description while style is the personal type of narration like what words they use or grammatical constructions. Theme is the underlying idea while the voice is seen through the tone, whether it's dark and broody or joyful or anything similar.
Procrastinate and my answer has to have 20 letters so this is what I’m doing
Answer:
Today I went to the zoo. I saw a (silly) (Monkey) jumping up and down in its tree. He (run, ran) (quickly) through the large tunnel that led to its (cozy) (nest). I got some peanuts and passed them through the cage to a gigantic gray (elephant) towering above my head. Feeding that animal made me hungry. I went to get a (delicious) Scoop of ice cream. It filled my stomach. Afterwards I had to (leave) (early) to catch our bus. When I got home! (hug, hugged) my mom for a (wonderful) day at the zoo.