POE works well here, too:
A) is out of scope: though national planners seem to be part of government, there is nothing about a subsidy in there.
B) is an obvious overbroad, red-flag wrong answer
D) trade imbalances between countries? out of scope
E) the conclusion of the argument is talking about a plan to solve the problem, so the choice that supports this most must be related directly to the conclusion. C) relates perfectly, E) speculates about a policy that will make things worse, which provides no info on a better way to solve the problem, which is the crux of the question.