What do Nakarattars of Tamil Nadu represent ?

The correct answer is Option (3) → Caste Based banking system

Option (3) Caste Based banking system — Correct. The Nakarattars of Tamil Nadu loaned and deposited money with one another in caste-defined social relationships. Public confidence came not from a government-controlled central bank but from the reputation and reserve deposits shared within the caste. In other words, the Nakarattar banking system was a caste-based banking system.

Option (4) Dominant Caste — Incorrect. A dominant caste is a numerically large landowning caste that dominates a region economically and politically, such as the Jats or the Reddis. The Nakarattars are known for their trading and banking networks, not for owning land in a region.