I think when looking at why (B) is incorrect, it is important to note the difference between "A few" and "few" (answer B states "FEW companies")
To quote mattsherman from another Manhattan LSAT forum,
mattsherman Wrote:If you say, "a few A's are B's," that would imply some (lets say 2 - maybe 3 - or more)
If you say, "few A's are B's," that would imply that while some A's are B's, that most A's are not B's. And it's the latter form that the test-writers typically utilize in the construction of the chain of reasoning.
Applied to (B):
While SOME companies in Ostronia that have received gov sub have taken the needs and desires of their customers into account, MOST companies that have received gov sub have NOT taken the needs and desires of their customers into account.
The stimulus mentions NO company that has received subsidies that TOOK customer need into account, so the first part of (B) (While SOME companies~) doesn't stand.
Also, we only know about ONE company that has received gov sub that has NOT taken customer need into account, which is the railroad company. ONE company is NOT ENOUGH to say MOST, so the second part of (B) (MOST companies that have ...) doesn't stand either.
To conclude, (B) is too broad and/or too extreme in terms of degree.
If (B) had actually stated "A few", it would be totally incorrect as "A few" is similar to "Some", yet the stimulus doesn't mention ANY company that has received gov sub that TOOK customer needs into account. Thus, there is no way for us to know if this is true, and it cannot be the correct answer for a must be true question.