Select the most appropriate option to fill in the blank.

My sister treats me well in the morning but at night she becomes ______.

awful

The most appropriate option to fill in the blank is awful.

The sentence is about the sister's change in behavior from morning to night. The word "awful" means extremely bad or unpleasant. It is the most appropriate word to use in this context because it describes the sister's behavior at night, which is unpleasant and unkind.

The other options are not as appropriate.

• Eloquent means using language effectively and expressively. This does not make sense in the context of the sentence because the sister's behavior is not described as being expressive or effective.
• Exemplary means setting a good example. This does not make sense in the context of the sentence because the sister's behavior is not described as being good or exemplary.
• Acceptable means good enough to be used or considered. This does not make sense in the context of the sentence because the sister's behavior is not described as being good enough to be accepted.