I think its an Idiom. I don't see like or as. So no simile. I don't see he is something like a marshmallow. - No metaphor. I also don't see a non-human thing doing human things- the grass was dancing in the wind. My answer would be an idiom.
Hope this helps!
PRO gress,,PRE conceived, PRE cede, POST mortem(?), POST script, PRE amble ... perhaps ?
Answer: A
Explanation: I did the quiz and it was a