In sentence (d), the error is the use of the word "crucially." The correct word should be "crucial." "Crucially" is an adverb, which means it modifies verbs, adjectives, or other adverbs. "Crucial" is an adjective, which means it modifies nouns. In this sentence, it is describing "first impressions," which is a noun phrase. So, 'crucial' (adjective) is required in place of 'crucially' (adverb). Hence, (d) is the correct answer.
Corrected sentence: He meticulously prepared for the interview, knowing that first impressions are crucial and can significantly impact the outcome.
The rest of the sentences are both grammatically and contextually correct.
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