Because "candid" means truthful and straightforward, or frank, the best answer choice is "truthful."

When something is “legitimate” it is in accord with the laws that would pertain to that class of things. For example, one could speak of a “legitimate action” as being one that is legal. Also, in a more extended sense, it can indicate conformity to the general laws of rationality or that a given thing is rightfully done in a given circumstance. For instance, a “legitimate critique,” is one that is valid given the data of the original argument. Such a critique justly finds something wrong with the argument and is therefore called “valid” or “legitimate.”

The word “specious” comes from the Latin for “appearance” or “beautiful.” When something is “specious,” it appears to be correct but really is not. It is merely apparent. Therefore, it misleads the person who considers it. Often, one will speak of “specious reasoning,” describing thereby some argument that appears to be plausible when in fact it is really false.

"Marginal" is an adjective that can besides meaning "of, relating to, or situated at the edge or margin of something," can also mean " of secondary or minor importance; not central." So, we need to pick out an adjective that means something like "of minor importance." Neither "crucial" nor "monumental" can be the correct answer, then, because each word is an antonym of "marginal," not a synonym. "Negligible," however, is an adjective that means "so small or unimportant as to be not worth considering; insignificant," and because it is the answer choir that is closest in meaning to "marginal," "negligible" is the correct answer.

"Noteworthy" means important or interesting. "Irritating" means annoying or bothersome. "Cryptic" means mysterious or puzzling. "Intelligent" means well-informed or smart. "Brutal" means violent and vicious.

“Frivolous” means purposeless and foolish, often specifically when serious purpose was expected. Thus, the correct answer is "inane," which means goofy and idiotic. As for the other answer choices, "listless" means languid or lethargic; "dour" means dreary and stern; "aristocratic" means having to do with historical high classes; and "pliable" means able to be bent.

The “margins” of a piece of paper are the edges on which nothing is normally written. When someone takes “marginal notes,” he or she writes in this space—as when someone writes in the margins of a book to keep notes on the text being read. To say that something is “marginal” is to imply that it does not sit “in the midst of the important things” but is merely “on the edges.” For this reason, the word is often used to describe something that is believed to be unimportant. For example, someone might say, “His remarks were really of marginal significance for the decision, for he did not know much about the topic.”

"Monumental" means very large or very important, so "significant" is the answer choice closest in meaning to "monumental." As for the other answer choices, "atrocious" means terrible and evil, "petrified" means turned to stone or so afraid that one cannot move, "statuesque" means stately and beautiful, and "fervent" means zealous.

"Negligible" means insignificant or unimportant. "Thrifty" means economical or frugal. "Canceled" means called off or erased. "Viable" means reasonable or practical. "Sarcastic" means nasty or mocking in speech. 

"Expendable" means superfluous or unnecessary. "Erudite" means well-educated and cultured. "Dogmatic" means dictatorial or opinionated. "Pedantic" means bookish or overly precise. "Extravagant" means lavish, indulgent, or wasteful.