Final answer:
The most logical response to complete the sentence 'violon est-ce que tu achètes?' is 'Quel'.
Step-by-step explanation:
The most logical response to complete the sentence 'violon est-ce que tu achètes?' is Quel. This is the correct form of the word 'quel' in its masculine singular form, which agrees with the noun 'violon' (masculine singular) in the sentence.
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