Clearly the government's argument is flawed because it is still consistent with them destroying evidence, i.e. there being no evidence is consistent with the government destroying the evidence. Answer choice (E) states that the government effectively disproves the charge made on behalf of the defendant. If that were the case, then there would be no error in the government's argument. But, there clearly is, since they did not give us any evidence to support their conclusion - their evidence is consistent with the attorneys' claim against the government.
That is why (E) is not the correct answer.
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