This is an official GMATPrep Problem.
So it's reliable then
Whenever you see an obscure idiomatic construction (on this one is correct, but obscure), elimination is the best strategy. We can immediately narrow it down to choices (C) and (E) because the word 'so,' when used to indicate the degree of extremity, should be accompanied by 'that' (or 'as to,' but that's not an option). And (C) clearly breaks parallelism because the phrase set off by commas doesn't
have the word 'so'
So, awkward through it is, (E) must be correct. In this case, even though we're missing the verb which makes it sound awkward, (E) is the only answer choice that has two parallel 'so [descriptor] that [consequence] construction, so it's the best answer choice available.
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