Critical Reasoning (CR) | If the check valves in nuclear power plants do not function properly,

I am still NOT clear with the explanation of option A above. Can someone elaborate more on why option A is incorrect. Though I picked E as the answer but was doubtful between A and E.

Please evaluate my reasoning for optionA.

(A) Approximately 80 percent of accidents in nuclear power plants are attributable to failures in piping systems. As per my understanding of the above argument, this option statement slightly strengthens the conclusion instead of weakening it. If 80% or majority of nuclear
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