Magoosh official solution :
Split #1a: subject-verb agreement. The main subject is "the Battle of Antietam", a singular noun. The main verb, at the beginning of the underlined section, must be singular as well, not plural. Choices (A) & (C) & (E) have singular verbs, but choices (B) & (D) make the mistake of having plural verbs, "rank" and "have" respectively.
Split #1b: let's look at the tenses of these verb. Choice (A), "ranks", and choice
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