Sentence Correction (SC) | Re: QOTD: The peaks of a mountain range, acting like

(C) crests and troughs that remain stationary although the air that forms them is moving rapidly, is
(E) stationary crests and troughs although they are formed by rapidly moving air [/list]

(C) emphasizes this fact much more clearly than (E) does. Fun stuff. (C) is the best answer.