Explanation:

- Absurd: This word describes something that is wildly unreasonable or illogical.

- Appropriate: Suitable or proper in the circumstances, but not directly contrasting "absurd."

- Adequate: Sufficient or acceptable in amount or quality. Not directly opposing "absurd."

- Abrupt: Sudden or unexpected; not relevant as an antonym of "absurd."

- Reasonable: This term means being fair and sensible, making it the direct opposite of "absurd."

?? Correct answer: Option 4 - Reasonable is indeed the antonym of "absurd." It represents logical and sensible ideas or actions, contrasting the illogical nature of "absurd."