The correct answer is: c) Andhra Pradesh.
The merger of the Telangana region with Andhra state in 1956 created the united state of Andhra Pradesh. The merger was a result of the States Reorganisation Act, 1956, which was passed by the Indian Parliament. The Act was aimed at creating a more equitable distribution of resources and power among the states of India.
The Telangana region was part of the Hyderabad State, which was ruled by the Nizam of Hyderabad. The Andhra state was part of the Madras Presidency, which was ruled by the British. The merger of the two regions created a new state, Andhra Pradesh, with a population of over 40 million people.
The merger was not without its challenges. The Telangana region was predominantly Muslim, while the Andhra region was predominantly Hindu. There were also concerns about the economic viability of the new state. However, the merger was ultimately successful, and Andhra Pradesh has become one of the most prosperous states in India.
The other options are incorrect. Option a) Telangana is the name of the region that was merged with Andhra state in 1956. Option b) Rayalaseema is another region in Andhra Pradesh. Option c) Madras State was the name of the state that Andhra Pradesh was part of before the merger. Option d) is not a valid option.