Explanation: The declaration of India as a nuclear state is a significant event in the history of India's nuclear policy and international relations. This declaration was made by Atal Bihari Vajpayee, who was the Prime Minister of India from 1998 to 2004. The context of this declaration is closely tied to the Pokhran-II nuclear tests, which were conducted in May 1998.
The Pokhran-II tests were a series of five nuclear bomb tests conducted by India at the Indian Army's Pokhran Test Range in Rajasthan. These tests were a continuation of the earlier Pokhran-I tests conducted in 1974, which were the first nuclear tests by India. The Pokhran-II tests were a response to the nuclear tests conducted by Pakistan in 1998, which heightened tensions in the region.
Following the successful completion of the Pokhran-II tests, Atal Bihari Vajpayee, in his capacity as Prime Minister, declared India a nuclear state. This declaration was a significant moment in India's nuclear policy, as it marked India's emergence as a nuclear power and its willingness to use nuclear weapons for self-defense. The declaration also had implications for India's international relations, particularly with countries like the United States and other nuclear powers.
It is important to note that the declaration of India as a nuclear state was not just a political statement but also a strategic decision. It was aimed at enhancing India's security and deterrence capabilities in the face of regional and global threats. The decision to conduct the tests and declare India a nuclear state was a result of a complex interplay of political, strategic, and technological factors.
In conclusion, the correct answer is Atal Bihari Vajpayee, who declared India a nuclear state following the successful Pokhran-II nuclear tests in 1998. This event is a crucial part of India's nuclear history and its broader strategic and diplomatic landscape.