The correct answer is Tamil Nadu Tourism Development Corporation (TTDC).
TTDC is a state government undertaking established in 1971 to promote tourism in Tamil Nadu. It is responsible for developing and maintaining tourist infrastructure, marketing Tamil Nadu as a tourist destination, and providing information and assistance to tourists.
The Ministry of Tourism, Government of India is responsible for formulating and implementing national policies and programs for tourism development in India. It also provides financial assistance to state governments for tourism development.
The Indian Association of Tour Operators (IATO) is a non-profit organization that represents the interests of tour operators in India. It promotes tourism in India and provides training and support to its members.
The Federation of Hotel & Restaurant Associations of India (FHRAI) is a non-profit organization that represents the interests of hotels and restaurants in India. It promotes tourism in India and provides training and support to its members.
In conclusion, the primary agency responsible for tourism promotion in Tamil Nadu is the Tamil Nadu Tourism Development Corporation (TTDC).