The correct answer is (a). The Buddha Circuit Express is a tourist train that was launched by the Indian Railways in 2018. It covers a circuit of Buddhist pilgrimage sites in Uttar Pradesh and Bihar. The train was launched in collaboration with the governments of Uttar Pradesh and Bihar.
Option (b) is incorrect because the train was launched in collaboration with the governments of Uttar Pradesh and Bihar, not just Uttar Pradesh.
Option (c) is incorrect because the train was launched in collaboration with the governments of Uttar Pradesh and Bihar, not just Bihar.
Option (d) is incorrect because the train was launched in collaboration with the governments of Uttar Pradesh and Bihar, not Japan.