Final answer:
Robi Chatterjee feels he is Indian due to the diversity of languages, unity of culture, and ancient history.
Step-by-step explanation:
In response to Rushdie's question about whether India "exists," Robi Chatterjee gives the reason that he feels he is Indian due to the diversity of languages, the unity of culture, and the ancient history of the country. India is known for its vast number of ethnic groups, languages, and religions, and despite political diversity and competing states in the past, a shared identity based on Hindu practices and beliefs has held the country together.