Diction; Logical predication
The sentence as written is not stated clearly. For example, it is unclear what
is shaped so smoothly and perfectly; it could be either the airplanes or
the wings. Upon considering the likely intended meaning, along with a review
of the other answer choices, it seems most likely that the phrase is intended to
modify frictionless wings.
Next, we need to consider whether it makes more sense to say that the wings
are smooth or shaped smoothly. This issue can be determined only by
considering the most plausible intended meaning rather than by considering
just the grammar of the sentence. The idea of being smoothly shaped would
seem already to be part of the idea of being shaped perfectly, and therefore it
is redundant. On the other hand, having a surface that is very smooth would
be crucial in a quest to make an airplane wing frictionless; for this reason, it
makes sense to point out that the wings themselves are smooth.

A. This choice is incorrect for the reasons stated above.
B. Correct. Given the repetition of the word wings, it is clear that what
follows modifies wings and not airplanes. Describing the wings
as smooth and perfectly shaped clearly conveys what is most likely
intended.
C. In this version, note that shaped is modified. For this reason, proper
grammar requires that the adverbs smoothly and perfectly are needed
rather than the adjectives smooth and perfect. However, as discussed
previously, the intended meaning of the sentence would be better
conveyed if we used the adjective smoothto modify wings rather than the
adverb smoothly to modify shaped.
D. It is initially unclear what is being described as having been shaped in
such a smooth and perfect manner; it could be either the airplane or its

wings. Even if that were clarified, however, the sentence would be flawed:
the sentence is intended to describe the wings themselves, not
the manner in which the wings were shaped. That is, this wording could
be interpreted as referring to the nature of the wings themselves or to the
process through which they were made. This ambiguity makes the
meaning of the sentence unclear.
E. This version is very awkwardly worded, mainly because of having been.
Furthermore, this version describes the act of shaping the wings. Because
the sentence is instead meant to describe the wings themselves, this
choice is incorrect.