Final answer:
The word that best completes the sentence is 'convoluted'.
Step-by-step explanation:
The word that best completes the sentence is convoluted. The sentence implies that the system for keeping the files is complex and confusing, hence the word 'convoluted' fits appropriately. This means that the system is intricately twisted or coiled, making it difficult to understand. The other words given in the options do not convey the same meaning as 'convoluted'.
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