Which type of adverb is used in the following sentence?

"He worked hard to achieve success."

Adverb of Manner

The correct answer is OPTION 2 -Adverb of Manner

An Adverb of Manner describes how an action is done.
In the sentence, the word "hard" tells us how he worked — it shows the way or manner in which he did his work.
Since it explains the manner of working, "hard" is an adverb of manner.

• If an adverb answers "how?", it is an adverb of manner.

• If an adverb answers "why?", it is an adverb of reason.

• If an adverb answers "when?", it is an adverb of time.

• If an adverb answers "where?", it is an adverb of place.