GMAT Critical Reasoning (CR) | Re: Naima: The proposed new computer system, once we fully implemented

Agreed. I think the key is to understand the stimulus like this:
Naima: New system is more efficient. Therefore, we should update immediately.
Nakai: Regardless of efficiency, it costs us too much money and time to update. Wherefore, we should not update immediately (if at all).

Put this way it is obvious that A cannot be the answer.

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