"Lavish" is an adjective that means "sumptuously rich, elaborate, or luxurious," "very generous or extravagant" when used of a person, or "spent or given in profusion." So, neither "sparing" nor "cheap" can be the correct answer because each of these words are antonyms of "lavish," not synonyms. "Luxurious," however, means "extremely comfortable, elegant, or enjoyable, especially in a way that involves great expense," or "giving self-indulgent or sensuous pleasure." So, because it is the answer choice closest in meaning to "lavish," "luxurious" is the correct answer.

"Costly" is an adjective that means either "costing a lot; expensive" or "causing suffering, loss, or disadvantage," so we need to pick out an adjective that means something like "costing a lot" or "causing suffering." "Cheap" cannot be the correct answer, then, because "cheap" is an antonym, not a synonym, of "costly." Since "pricey" is an adjective that informally means "expensive," "pricey" is the answer choice closest in meaning to "costly," making "pricey" is the correct answer.

"Marvelous" is an adjective that means either "causing great wonder; extraordinary" or "extremely good or pleasing; splendid." So, we need to pick out an adjective that means something like "extraordinary" or "splendid." "Mundane," then, cannot be the correct answer, because "mundane" means "lacking interest or excitement; dull," making it an antonym, not a synonym, of "marvelous." "Phenomenal," however, is an adjective that means " very remarkable; extraordinary," and because "phenomenal" is the answer choice closest in meaning to "marvelous," "phenomenal" is the correct answer.

“Lucrative” is an adjective that means “producing profit,” so we need to pick out an answer choice that means something like “producing profit.” That means that “unprofitable” cannot be the correct answer, because “unprofitable” can mean “not yielding profit” when referring to a business or activity, making it an antonym, not a synonym, of “lucrative.” “Profitable,” however, is an adjective that means “yielding profit” when referring to a business or activity, and because “profitable” is the answer choice closest in meaning to “lucrative,” “profitable” is the correct answer.

"Expensive" means costly.

"Paltry" means incredibly small and meaningless. "Meager" is the best choice because it also means worthless or not enough. 

The word "lucrative" means profitable or moneymaking. The best choice is "advantageous" because it means profitable or useful.

"Valuable" is defined as worth a great deal of money. Since "expensive" things are highly priced, "expensive" is the best answer choice. "Worthless" is an antonym of "valuable."

The word "faulty" is an adjective that means—unsurprisingly—having a fault or faults. A "faulty" tire is one that does not spin correctly, and a "faulty computer" is one that does not work as it should. You might get confused looking at the options and think that perhaps "trembling" is a good good answer. A "fault line" is an imperfection in the earth's crust, leading to earthquakes at times. However, the word "faulty" mere indicates imperfection or flaws. Therefore, "flawed" is the best answer.

"Elite" means having superlative qualities. "Best" means better than all other options. Given how similar these words' meanings are, "best" is the synonym for "elite."