htchanit wrote:
the correct is "(a) balance its trade while its standard of living rises", isn't it ?
yes.
this is one of the few passages on which they actually tell you, more or less explicitly, the correct answer; the primary challenge is to piece together the antecedent of the word both in the second sentence.
i.e., the second sentence of the passage says "both are required simultaneously". once you figure out what this is referring to, you've got it.