We often use reaction in its weak sense of being a “response.” This is an acceptable (and most appropriate) meaning, but it is not found among your options. In a stronger usage, it can mean “a strong action or set of actions in response, often political.” For instance, one could say, “The new legislation requiring all citizens to pay an additional twenty percent in taxes caused a huge reaction from almost all classes of citizens.” Here, “reaction” takes on the stronger meaning of “backlash.”

Likely, you have heard the expression, “the only recourse,” as in, “A presidential pardon was the only recourse that the man had to lift the crime from his record.” The word generally means, “Means of alleviating a situation,” or even more generally, “Choice or option.” Thus, when one says, “He had recourse to the support of his family during his financial difficulties,” this means, “He had the option to go to his family for aid.”

"Panegyric" and "elegy" both mean praise or warm words. "Rant" means a tirade or yelling. "Probity" means fairness or honesty. "Proclivity" means an inclination or habit. "Odyssey" means a journey or excursion. 

"Magnanimity" and "chivalry" both mean generosity. "Avarice" means extreme greed. "Cupiditiy" also means extreme greed or acquisitiveness. "Maxim" means a saying or aphorism. "Myriad" means a lot of something.

"Credence" means acceptance or trust, so "acceptance" is the correct answer. None of the other answer choices are close in meaning to "credence": "conflagration" means a large fire; "renaissance" means a rebirth or renewal; "investment" means something given or lent with the expectation of a return; "apprehension" means anxiety or fear. 

While "anarchy" and "monarchy" are both types of government, they do not convey the same meaning as "democracy." The word closest in meaning is egalitarian.

The “nomenclature” of a given discipline is the set of terms specific to it. For example, one can speak of the “binomial nomenclature” that is used to describe animal species (e.g. man is homo sapiens). One can thus say that a given “nomenclature” is the set of “terminology” for a discipline. This is the best option among those provided.

The word “narrative” comes from the Latin for “to tell” as in “telling a story.” The word “storyteller” is close to this—to “narrator” not “narrative.” Although one might think of the enumeration of things as being a sort of narrative, it is more proper to say that a “chronicle” provides a narrative. A “chronicle” is an account of historical events told as a narrative according to time. The word “chronological,” meaning “related to time” is related to “chronicle.”

The “milieu” of something is the “middle location.” A given “milieu” is the “midst” in an expression like “in the midst.” Therefore, we call a thing or person’s “milieu” his or her environment. For instance, we may speak of the “political milieu” of a given family that has strong ties to political factions, or we may use “milieu” to indicate the general socioeconomic environment in which someone lives.

The word altercation comes from the Latin for “to dispute or argue.” It means roughly the same in English. For example, one might say, “After the large altercation between the two men, their friends decided not to invite them to the party, fearing that they would argue in public and disturb the peace of the gathering.”