For match the reasoning questions, you want to simplify the subject matter as much as possible in order to see the reasoning between elements. We can think of the argument as follows:
People who usually do X then start doing Y feel less anxious.
Therefore, if you do X, you can probably become less anxious by doing Y.
There is a correlation/causation issue in the argument, so we should expect that our correct answer will exhibit that same flaw.
The four wrong choices for a question such as this one will vary, in subtle or obvious ways, from the structure of the original argument.
Here's a quick list of some of the ways in which the answers don't match up with the argument:
(B) is about "certain" small companies, whereas the original argument is more of a generalization. (If you don't think this is a significant difference, think about the difference in meaning between the phrases "people will survive" and "certain people will survive.")
(C) "Must" helps us eliminate this answer quickly. It doesn't match the degree of "probably."
(D) "Only if" is very different in meaning from the original argument (the argument never said getting 8 hrs of sleep is "only" way of feeling less anxious.)
(E) is tempting, but "could become financially strong" is very different from getting stronger. Also, this "never" (which relates to something different than the "never" in (B)) is also not a great match with the argument.
That leaves (A), the correct answer. If we think about structure, it matches up very nicely with the original argument.
Let's look again quickly:
People who usually do X then start doing Y feel less anxious.
Therefore, if you do X, you can probably become less anxious by doing Y.
And let's match (A):
Companies that didn't advertise on internet start to do so and financial situation improves.
Therefore, if you haven't advertised, can probably improve financial situation by doing so.
This argument has the correlation/causation flaw and the right degree.
Hope that helps!
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