The correct answer is: a) Generation, transmission, and distribution.
Unbundling of the electricity sector is the process of separating the different activities involved in the generation, transmission, and distribution of electricity. This is done in order to create a more competitive market and to improve efficiency.
In Andhra Pradesh, unbundling was carried out in 2002. The state electricity board was split into three separate companies: one for generation, one for transmission, and one for distribution. This has led to increased competition in the generation and distribution of electricity, and has also resulted in lower prices for consumers.
Option b) is incorrect because thermal and renewable power are both forms of generation. Option c) is incorrect because urban and rural power supply are both forms of distribution. Option d) is incorrect because public and private sector power companies are both involved in generation, transmission, and distribution.