The words "stellar" and "fantastic" are both positively charged expressions meaning wonderful! The other answer choices do not have the same meaning. The other options all have distinctly negative connotations.

"Credible" means "believable," plausible or rational.

"Authorized" means approved, certified or lawful.

"Corny" means old fashioned, contrived or stupid.

"Fortunate" means having good luck, affluent or prosperous.

"Impartial" means fair and unprejudiced.

"Significant" and "consequential" are adjectives describing things that are important and have meaningful consequences. The other words do not share this meaning. Words like "symbolic" may seem to come close; however, the meaning of "symbolic" is not sufficiently relevant to that of "significant." The remaining words are actually antonyms of the words "significant" and "consequential."

"Cryptic" means "secret," encoded, or obscure in meaning.

"Portentous" means ominous or having great significance or meaning.

"Pretentious" means snobby, conceited or grandiose.

"Prevalent" means wide-spread, common, accepted.

"Relevant" means pertinent, appropriate, or related to something.

The adjective "covert" means meant to be undertaken without people knowing or noticing, secretive, stealthy. Additionally, "terse" means brief, concise, to the point; "senile" means mentally weakened due to old age; "congenial" means friendly and agreeable; "illiterate" means not literate, not able to read or write.

The adjective "confidential" means intended to be secret, private and personal information. Additionally, "elegant" means dignified and refined, being stylish and graceful; "harmonious" means either peaceful or pleasing-sounding; "frivolous" means having no purpose or use; "stifling" means oppressive, uncomfortably hot.

The adjective "preposterous" means absurd, ridiculous, too silly to be believed. Additionally, "opaque" means not allowing light to pass through, whereas "transparent" means allowing light to pass through; "obtuse" means dull-witted, mentally slow, whereas "acute" means sharp-witted, mentally quick.

Novel means something is new.

"Stagnant" means still, not flowing.

“Eternal” is an adjective that means “lasting forever; without end or beginning,” so we need to pick out an answer choice that means something like “lasting forever.” That means that “ephemeral” cannot be the correct answer, because “ephemeral” means “lasting for a very short time,” making it an antonym, not a synonym, of “eternal.” “Perpetual,” however, is an adjective that means “never ending or changing,” and because “perpetual” is the answer choice closest in meaning to “eternal,” “perpetual” is the correct answer.