Since "cold" and "hot" are opposites, we're looking for an answer choice in which the two words are opposites. Since "day" is the opposite of "night," "day is to night" is the correct answer.

Both sets of words are antonyms.  

Both sets of words are antonyms. 

Both of the sets are antonyms.  

Since "hungry" and "full" are opposites, we need to pick out another pair of words which are also opposites. Since "exhausted" ("very tired") is an opposite of "energetic," "exhausted is to energetic" is the correct answer.

"Welcome," when used as an adjective, means "of a guest or new arrival: gladly received," and "excluded" is an adjective that means "deny (someone) access to or bar (someone) from a place, group, or privilege," so the two words are antonyms. That means that we need to pick out an answer choice that consists of two antonyms. "Ready" cannot be the correct answer, then, because "ready" is a synonym, not an antonym, of "prepared." "Unready," however, is an antonym of "prepared," just like "welcome" is an antonym of "excluded," so "unready" is the correct answer.

“Friend” and “enemy” are nouns that are opposites, or antonyms, so we need to pick out an answer choice that consists of two nouns which are also opposites. While “confidence is to shyness” and “justice is to fairness” might each look like a potentially correct answer, “justice” is a noun that means “the quality of being fair and reasonable,” so “justice” and “fairness” are synonyms, not antonyms, and “justice is to fairness” cannot be the correct answer. “Confidence,” however, is a noun that means “a feeling of self-assurance arising from one’s appreciation of one’s own abilities or qualities,” while “shyness” is a noun that means “the quality of feeling nervous and uncomfortable about meeting and talking to people.” So, because “confidence” is an antonym of “shyness” just as “friend” is an antonym of “enemy,” “confidence is to shyness” is the correct answer.

"Active" means energetic and lively and is an antonym of "inactive." To solve this analogy, you need to figure out the best available antonym of "amateur." Someone who is an "amateur" is not paid for their work, so the only acceptable antonym is “professional.” None of the other answer choices are antonyms of "amateur": "employed" means having a paid job, "income" is the money one earns by working; and "taxes" are the portion of money that the government takes from your income.

"Remember" is an antonym of "forget." So, to solve this analogy, you have to figure out the best antonym of "prevent." "Prevent" means to stop someone from doing something, so the best antonym is “allow,” which means to let someone do something. To help you, "enigmatic" means mysterious, and "forbid" means the same thing as "prevent", or in other words, they are synonyms.

"Cowardly" is an antonym of "brave," so to solve this analogy, you have to figure out the best antonym of "ignorant." Someone who is "ignorant" is stupid, and does not know very much. The word that is the best opposite of "ignorant" is “wise,” which means very intelligent. To help you, "vulnerable" means in danger, and "timid" and "meek" both mean shy.