1. The peaks of a mountain range, acting like rocks in a streambed, produce ripples in the air flowing over them: the resulting flow pattern, with crests and troughs that remain stationary although the air that forms them is moving rapidly, are known as “standing waves.”
(A) crests and troughs that remain stationary although the air that forms them is moving rapidly, are
(B) crests and troughs that remain stationary although they are formed by rapidly moving air, are
(C) crests and troughs that remain stationary although the air that forms them is moving rapidly, is
(D) stationary crests and troughs although he air that forms them is moving rapidly, are（C）
(E) stationary crests and troughs although they are formed by rapidly moving air, is
请问C中的crests and troughs that remain stationary 和D中的stationary crests and troughs 哪个在理解上更容易引起歧义.
c: crests and (troughs that remain stationary) vs (crests and troughs) that remain stationary
d: (stationary crests) and troughs vs stationary (crests and troughs)
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