The correct answer is: A. Zilla Panchayat t Block Panchayat + Gram Panchayat Gram Sabha
The Panchayati Raj system is a three-tier system of local self-government in India. It consists of the Gram Panchayat (village council), the Panchayat Samiti (block council), and the Zilla Parishad (district council). The Gram Sabha is the lowest level of the Panchayati Raj system and is composed of all the adult members of a village. The Gram Panchayat is responsible for the development and management of the village. The Panchayat Samiti is responsible for the development and management of a group of villages. The Zilla Parishad is responsible for the development and management of a district.
The Khap Panchayat is a traditional caste council that exists in some parts of India. It is not a part of the Panchayati Raj system.
The Nagar Panchayat is a type of local self-government body that exists in urban areas. It is not a part of the Panchayati Raj system.