Sentence Correction (SC) | Re: Since the 1930's aircraft manufacturers have tried to build airplanes

Since the 1930's aircraft manufacturers have tried to build airplanes with frictionless wings, shaped so smoothly and perfectly that the air passing over them would not become turbulent.


(A) wings, shaped so smoothly and perfectly --> wings shaped smoothly is wrong. wings are shaped so smooth is correct - soeliminate

(B) wings, wings so smooth and so perfectly shaped --> no errors wings are shaped so smooth and perfectly is correct grammar

(C) wings that are shaped so smooth and perfect
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