GMAT Critical Reasoning (CR) | Re: One of the limiting factors in human physical performance is

hello everyone is saying about weakening...
i chose different reasoning.

premise: oxy level directly propositional wit performance
premise2: oxyrich supplying water wit more oxygen content n claims to improve performance.

conclusion: it is useless.
evidence/fact: oxy only through lungs. and fact is strengthening conclusion.

so want a strenghtener n NOT a weakner.

hence B should be the ans

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