According to some economists, Japan is in danger of plunging into a depression that, with double-digit unemployment, could severely strain a society that regards lifetime employment as a virtual right of citizenship.
(A) that, with double-digit unemployment, could severely strain
(B) that, because of double-digit unemployment, could be a severe strain for
(C) with double-digit unemployment, and it could severely strain
(D) with double-digit unemployment and could be a severe strain
(E) with double-digit unemployment and could severely strain
A is my choice.
C is not the choice due to the ambiguous "it" .
D is wrong because " strain" , as a noun here, should have a certain preposition as it's right followed by other noun " a society".
E is out because the subject of " could severely strain" here seems to be " Japan" , not "depression".
B:" strain for" sounds unidiomatic.