No A is wrong because the author is not uncertain about A. The author is certain that you cannot assume increase in population leads to increase in political activism. This is precisely because he is uncertain about to what extent the population shared the opinions of the leaders, which is D.
No A is wrong because the author is not uncertain about A. The author is certain that you cannot assume increase in population leads to increase in political activism. This is precisely because he is uncertain about to what extent the population shared the opinions of the leaders, which is D.