Explanation:

- Option 1: Ashoka

- Ashoka was a famous emperor of the Maurya dynasty.

- He ruled much later than the time of the Haryanka dynasty.

- Option 2: Prasenajit

- Prasenajit was a ruler of the Kosala Kingdom.

- He was not associated directly with the Magadha or the Haryanka dynasty.

- Option 3: Bimbisara

- Bimbisara was indeed the first significant ruler of the Haryanka dynasty.

- He is known for expanding and strengthening the kingdom of Magadha.

- Option 4: Ajatshatru

- Ajatshatru was a successor of Bimbisara, also from the Haryanka dynasty.

- He was instrumental in further expanding the kingdom by conquering neighboring regions.