Choose the sentence containing Adverb of Affirmation from the following options:

Surely you are mistaken.

The correct answer is Option (3) - Surely you are mistaken.

An Adverb of Affirmation is used to express certainty, agreement, or confirmation about an action or statement.

1. He is far better now.

   • "Far" is an adverb of degree, modifying "better." It does not indicate affirmation.

2. This story is well written.

   • "Well" is an adverb of manner, describing how the story is written.

3. Surely you are mistaken.

   • "Surely" is an adverb of affirmation, expressing certainty that the listener is mistaken.

4. He therefore left school.

   • "Therefore" is an adverb of reason or cause, not affirmation.