Explanation:

- Karnataka is the largest producer of coffee in India. It benefits from ideal growing conditions, such as mild temperatures and ample rainfall.

- Tamil Nadu is also a significant coffee producer but not as prolific as Karnataka. It mainly focuses on the production of Arabica variety.

- Andhra Pradesh, while having coffee plantations in its hilly regions, does not match Karnataka's output levels.

- Kerala contributes to India's coffee production, especially in the Wayanad region, but again is less than Karnataka.

Karnataka is the correct answer.