"Unequivocal" means not subject to interpretation or more than one interpretation; in this case, there was only one way of explaining Van Gogh's death until new evidence arose. "Dubitable" here is an antonym of the correct word, meaning either open to doubt or questionable.

“Quiescence” means complacency or passive acceptance, which is the only answer choice that would infuriate someone with a desire to act.

“Autodidactic” describes someone who learns on his own and teaches himself. The first phrase starting with “although” indicates that the word in the blank must be incompatible with using a conversation partner.

Chuck is set up to be the opposite of Bill, who is quiet, so Chuck must be talkative. "Loquacious" means talkative, so it is the answer.

The word that fills in the blank must contrast with a teacher who rambles. Were Deborah’s teacher more "laconic" (that is, were he more brief and to the point), then he would not likely deliver rambling speeches. "Loquacious" and "garrulous" both mean talkative, while "pedantic" means strictly concerned with formal rules and book learning.

The sentence makes a contrast between those who “criticized” the mayor’s decision and the way others responded. The adjective in the blank describes how this other “small group” reacted. "Lauded" means praised, which is the antonym of "criticized," and thus best completes the sentence.

The word "liberal" is used in many ways today—most of which have political overtones. Its more general meaning is generous, coming from the Latin for "free." It is related to words like "liberty" and "liberate." "Liberality" is the character trait of being very free and generous with one's money. This sentence begins with "while," indicating that although many people thought one thing about Peter, those who knew him well knew something different. In contrast to liberality, "miser" works well. A miser is someone who hoards his or her money, avoiding spending it at all.

The "both . . . and" being used in the second clause helps to unpack why it was difficult to know what Justin would say. It seems that he would say conflicting things—hence the difficulty in guessing his next words. "Understatement" is a way of speaking that doesn't really address the true depths of some reality. For instance, a horrible murder might be called "kind of bad" by someone. This would be an understatement of the case. A great contrast to this is "hyperbole," meaning an expression that greatly overstates the case. For instance, someone might say that the day is the "coldest day ever" when it is not even at the point of freezing but merely brisk.

In contrast to being "inflexible," being "malleable" describes a temperament that literally is able to "bend" to the changing circumstances of life and living. The word is often used of substances—certain kinds of metal are more malleable than others. This contrast is indicated because of the introductory word "although." Although Thomas seemed to be one way—inflexible—he was in fact another—malleable.

Of the wrong answers, the one that is perhaps somewhat appropriate—though not completely correct—is "mendacious," meaning pertaining to lying. A "mendacious person" is a liar. (Perhaps "uncouth"—lacking good manners—is a temptation as well.) The general point, however, is a contrast. Ronald's friends are surprised because he is not acting morally upright—what a person with a scrupulous conscience would do. Therefore, he is acting in an immoral way. To be iniquitous is to be just that. "Iniquity" is another name for very immoral or unfair behavior.