Well put, EA!
And to add to that, the meaning in B isn't a logical meaning for the rest of the sentence. Note that the main thought begins with the word "Although":
Although government policy can influence productivity...
With that word "although" in the first clause, the second needs to have a meaning that runs counter to the first. You wouldn't say "Although it was raining, I carried an umbrella", because rain and umbrella go hand in hand - there isn't anything in the second half that runs counter to the thought in the first, so "although" just sits there as a signal of a surprise ending that never comes. You might, though, say "Although it was raining, I stayed dry with the help of my umbrella". That second half has a counter in it - rain should make you wet, but the "catch" in the second half is that that didn't happen.
So in this case, if we use "Although government policy influences productivity", we need a counterpart in the second half. And some government influence does not prohibit the ability of management decisions to have a great impact. You'd still expect that. But for management decisions to have at least as great an impact - that runs counter. The first half highlights how important government policy is; by the time we're done reading the first half it seems like the government is a primary factor in the industrial sector's performance. But "although" has set us up for a somewhat-surprising ending, and A delivers that by saying "yeah, but actually management decisions are at least as important as what we already told you was a big deal".
To summarize - "although" in the first clause of a sentence signifies that you need a somewhat "surprising" meaning in the second half...or at least something that runs a bit counter to what you saw in the first.
Brian Galvin
GMAT Instructor
Chief Academic Officer
Veritas Prep
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