GMAT Sentence Correction (SC) | Re: The musician Bob Marley, popular both in America and in Canada, is con

The correct idiom that has to be used in this sentence is both X and Y. Whatever preposition is used after X the same has to repeat after and. Hence "both in" has to be followed by "and in". The other rule is considered is not followed by any preposition which leaves us with only one correct answer "A."

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