When something is "optional," it is not required. Thus, you could say, "That homework was only optional." This means that you are not required to do that particular work. When something is voluntary, it is up to our choice—just like something optional. The word "voluntary" actually comes from the Latin "voluntas," which means will. Something voluntary is in the power of our willing. A "volunteer" does something of his or her own free will—that is, not out of a requirement or for a payment.

When we use "figurative" language, we use words in a way that is not literal. For example, I could say, "The sun is bright today."  This is literal language. However, if I were to say on a beautiful day, "The sun is happy today," this would be figurative language. Likewise, I could say, "She had a look on her face that could curdle milk." Well, maybe the person's face did show her displeasure. It certainly could not literally curdle milk! Thus, figurative language is symbolic or metaphorical.

Whenever we have something "in abundance," this means that we have a lot of it. The adjective "abundant" is used to describe something that is numerous and plentiful. Therefore, you could say, "I have an abundance of bread—indeed, enough to fill two whole baskets!" This means that you have a lot of bread. Your bread is "plentiful"!

The word "rural" is used as an adjective to describe an area that is not developed like a city. It is usually used as a synonym for "the countryside." There are few adjectives that mean "country-like" or "pertaining-to-the-countryside." Therefore, the only option provided here that is close is "agricultural." This is sometimes used as a synonym for "rural." People in the countryside often have agricultural businesses to make money, using the land to grow crops.

Whenever something is "precise," it is exact. We tend to talk about "precise measurements," often meaning the kinds of measurements that scientists might make. Also, people who are precise can at times be picky—very annoying about exact details. The only option that really expresses a correct synonym is the word "exact."

Whenever something is "enchanting," it draws our attention and keeps it. Thus, it is something that is captivating or delightful. Whenever we say, "It was an enchanting evening," we mean that it was a very delightful and wonderful evening. A story can be "enchanting" when it is delightful and captivates the attention of the listener or reader.

Whenever someone is "hostile," he or she is a foe. The primary meaning of "hostile" means unfriendly, in the sense that implies that someone or something is a kind of foe or enemy. Therefore, among the options given, the simple word "unfriendly" is actually the best option!

If someone flatters someone or something, it means that they compliment or praise that person or thing.

If someone makes an assertion, it means that they make a declaration or declare something in particular.

"Ascertain" is a verb that means "find something out for certain; make sure of." So, "forget" cannot be the correct answer, because it means the opposite of "ascertain." "Deduce," however, is a verb that means "arrive at a fact or a conclusion by reasoning; draw as a logical conclusion," and because it is the answer choice closest in meaning to "ascertain," it is the correct answer.