Sentence Correction (SC) | Re: Maxwell’s theory of Electromagnetism in 1865 was the first

Official Explanation Magoosh:

Split #1: the placement of "only". What do we wish to show is limited? The most natural phrasing is "was the only other": what is limited is the fact that, after the first, there's only one more. The phrase "only was the other" is awkward, as if the thing that needs to be qualified as limited is the verb, not the other. The answer choices that have "only" before some form of the verb, choices (A) & (C) & (D), are
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