Explanation:

- Option 1: Ashoka

- Ashoka was a famous emperor of the Maurya Dynasty.

- He is known for spreading Buddhism and the Kalinga War.

- Option 2: Mahapadma Nanda

- Mahapadma Nanda was the founder of the Nanda Dynasty.

- He is sometimes noted in texts for his conquests and power.

- However, there's no concrete historical evidence he claimed the title EKARAT.

- Option 3: Chandragupta Maurya

- Founder of the Maurya Dynasty and unified several Indian states.

- Known for consolidating the Indian subcontinent under one domain but not specifically for claiming the title EKARAT.

- Option 4: Ajat Shatru

- An important king of the Haryanka dynasty of Magadha.

- Known for his conflicts and expansion of Magadha’s territory.

Correct Answer: Option 2 - Mahapadma Nanda