Honestly, it comes down to what you think, and what you want to pen down, in the end. What kind of qualities do you think a good leader should have? A good leader, in my perspective, should undoubtedly be just, kind, merciful when the opportunity arises, without being too merciful. She/He should be giving and caring of the people she/he is the leader of. Those obvious things aside, a good leader should be confident in her/himself in their status, in their popularity, and finally, in themselves and their decisions, without being too confident so as to crossing into being arrogant.
A good leader should be brave and courageous, with no fear whatsoever of stepping up to protect her/his people. A good leader should be engaged with her/his people, and optimistic, never too pessimistic and getting her/his people down. He/She should be agile and adaptive, and should be self-motivated, as well as self-aware of everything going around him/her, and what should be done and what shouldn't be done, and what he/she is doing.
Most commonly "C", because they would want the reader to understand that something is different. Yes, they can change the style whenever they want to, but it would be more meaningful if they did it for a reason.
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.