Final answer:
The sentence 'Juan prefiere esa mantequilla' is grammatically correct.
Step-by-step explanation:
The sentence 'Juan prefiere esa mantequilla' is grammatically correct.
In this sentence, 'Juan' is the subject, 'prefiere' is the verb, and 'esa mantequilla' is the object. The verb 'prefiere' means 'prefers' in English, so the sentence translates to 'Juan prefers that butter.'
Since the sentence follows the correct grammar structure in Spanish with a clear subject, verb, and object, it is grammatically correct.
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