Although schistosomiasis is not often fatal, it is so debilitating that it has become an economic drain on many developing countries.

A. it is so debilitating that it has become an economic
B. it is of such debilitation, it has become an economical
C. so debilitating is it as to become an economic
D. such is its debilitation, it becomes an economical
E. there is so much debilitation that it has become an economical





OA: A


It will be helpful if someone can explain the right usage of So X that Y versus So X as to Y
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