Although this argument is causal rather than conditional, we can still use some conditional analysis on it. Answer C can be viewed as a Mistaken Negation, akanshalsat. The author argues that the spread of literacy before there is comprehensive education can help topple benign regimes. Perhaps look at that as this diagram:
Literacy + Comprehensive Education Topple Benign Regime
Answer C is:
Comprehensive Education Topple Benign Regime
That alone should be enough to kill it, because a conditional claim does not entail that the author assume a Mistaken Negation of that claim. But, let's apply the Assumption Negation Technique to it. Answer C, negated, would be something like "a comprehensive system of general might not be sufficient to preserve a benign regime." In other words, even if you have that system of education, a benign regime could fall. What does that do to the claim that without that system, benign systems might fall? Nothing! Both could be true - benign systems might be doomed either way, and it could still be that literacy without education makes the fall more likely or faster.
When faced with a conditional claim, the author assumes the contrapositive is true, but he need not make any assumptions about mistaken negations or mistaken reversals, and in fact those might actually hurt his argument.
I hope that makes it clearer!
#19 - Historian: The spread of literacy informs more people
Thanks for the above explanations! I thought answer choice D's language was too strong, i.e., that it was too much of a stretch to read "illegitimate" vs. "legitimate" reform from the historian's language. How can I distinguish between answer choices that are too extreme in language and not?
In this particular question legitimate reformers relates to the folks in the stimulus who have been called true reformers. The illegitimate ones are the ones who are called mere opportunists in the stimulus. So we are matching terms in order to see that this is not too extreme.
However, the more general answer would be to use the assumption negation technique for this question (since it is an assumption question). If you negate answer D then a general lack of education would not necessarily inhibit the ability to differentiate...(etc.). And if that were the case then the second, and after that the third, sentences in the stimulus would not necessarily be true. This means that negating Answer D has harmed the argument, and that makes it the correct choice.
Hope that helps,