Honestly, this is a question of opinion, but it should be easy to find the most logical answer through process of elimination. A seems okay, doesn't sound like a little kid said/wrote it, so I wouldn't eliminate it yet. B, to me, sounds like a little kid said/wrote it, so I would eliminate it. C, sounds like a mature, intelligent person said/wrote it, so I wouldn't eliminate it yet. D, the same as B, sounds like a little kid said/wrote it. Although B and D aren't bad sentences, they are very simple and 'young'. Now, back to A and C. Although A is descriptive and a good sentence, C has a better and more sophisticated word choice. So, I would go with C.
Hope this helps!