GMAT Sentence Correction (SC) | Re: Whereas lines of competition are clearly defined in the more

Pay attention to the non-underlined phraseone day , phraseone day can not modify the nouncompanies --> option B is wrong; instead, phraseone day should modify the verbcompete --> option A is correct.

PS: To modify a noun likecompanies in B, we should you anadjective or anothernoun . phraseone day here is anadverb .

Does all this make sense?
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