To the public’s great shock, the group recently voted into power on a platform of peaceable reform conducted .......... acts against existing branches of government as soon as the election was over.
The phrase “to the public’s great shock” is a key phrase—it tells you there’s a contrast between what was expected (“peaceable reform”) and what really happened. The correct answers must mean something like “violent rebellion.” Contumacious is a difficult vocabulary word, so we’ll use the process of elimination to go through all the answer choices. Choice (B) endemic means “inherent,” which doesn’t fit the context of the sentence. Choices (C) and (E), erratic and irresolute, both mean “unpredictable” or “uncertain.” If you weren’t sure of irresolute, consider its root, resolute, and think of a similar word, resolution in this case. A resolution is something you commit to doing, and irresolute is its opposite, “unsure” or “unable to make a decision.” These two words are plausible choices because they imply that the group didn’t fulfill its promises, but they don’t work in context. You need a contrast with “peaceable reform,” something that would result in people’s shock—unpredictability and uncertainty aren’t shocking. Choice (D) estimable, “worthy,” means the opposite of what you want. If you didn’t know the meaning of this word, you could consider its root, esti. Think of words with a similar root that you can define, such as esteem. Knowing that esteem has a positive tone, you could deduce that estimable does as well, making it incorrect. That leaves you with choices (A) and (F)— contumacious and seditious—both of which mean “rebellious” and are the correct choices.