The word "demonstrative" refers to something that is meant to explain some information. The best choice is "explanatory" because it shares the same definition as "demonstrative." Considering the other choices, "achievable" means able to be attained, "lacking" means not having, and "showy" means making a great display. 

"Didactic" means serving to instruct or teach, so "instructive," which means serving to instruct, is therefore closest in meaning. 

Something that is didactic may be "interesting," but this is possibly a characteristic of something that is didactic, rather than a definition. Therefore, "interesting" cannot be the correct answer. As for the other answer choices, "dynamic" means active or  changing and "candid" means honest.

The word "demonstrative" means serving the purpose of showing and explaining. The best choice is "show" as it is a part of the definition of "demonstrative."

The word "inane" means having no sense. So, "absurd," which means completely senseless, is the best choice. Considering the other choices, "eminent" means distinguished in rank, "smooth" means even on the surface, and "wordy" means talkative.

“Acute” can be used to describe a person in which case it refers to someone who is sharp-minded or quick-witted, or it can be used to describe an angle in a triangle, in which case it means measuring less than ninety degrees. When an angle is exactly ninety degrees we call it a “right” angle; when it is greater than ninety degrees we call it an “obtuse” angle. Just like how either a person or an angle can be “acute,” so too can a person or an angle be “obtuse." When a person is “obtuse,” we say they are dull-minded or slow-witted, or in other words, not easily understanding things that most other people understand. To provide further help, “transparent” means able to been seen through, “translucent” means partially able to be seen through, and “opaque” means unable to be seen through. The three words are used to describe how light passes through objects. A window is “transparent,” the ocean is “translucent,” and a brick wall is “opaque.”

"Frank" means honest, upfront, or candid, so "candid" is the synonym. 

“Cryptic” derives from the Greek word for "secret," so it makes sense that it means difficult to understand or having a hidden or secret meaning. "Mysterious" is thus the best answer. “Potent” means strong and powerful and is often used to describe medicine and solutions; “unfortunate” means unlucky, not fortunate; and "ghostly" means like a ghost or spectral; "somber" means severe, serious, and gloomy.

An “apocryphal” story is one that is probably not true, but widely believed to be true. This is closest in definition to "mythical." To provide further guidance, "foolish" means not clever, stupid; "succinct" means expressed clearly in as few words as possible; "accurate" means exact, precise, on target.

The word "salient" comes from a Latin word meaning to leap. If someone makes a salient point, it's as if that point is leaping out at you, leading to its meaning of prominent or relevant. Don't be deceived by false cognates, such as "saline" (salty), or "sale" (discounted).

"Erroneous" is an adjective that means "wrong; incorrect," so we need to pick out an answer choice that means something like "wrong." "Correct," then, cannot be the correct answer, because "correct" is an antonym of "erroneous," not a synonym. "Mistaken," however, is an adjective that means either "wrong in one's opinion or judgment" or especially of a belief, "based on or resulting from a misunderstanding or faulty judgment." Because "mistaken" is the answer choice closest in meaning to "erroneous," "mistaken" is the correct answer.