Sentence Correction (SC) | Re: In 1929, nearly 90 percent of the U.S. population attended

I am rather skeptical about the OA. Is the sentence structurally parallel around 'but'? We have a verbed clause on one side and a phrase on the other. Of course. it might be logically ok because of the ellipsis. But parallelism relies upon structural parallelism heavily to achieve its logical parallelism.

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