The correct answer is A. Rajasthan.
Jantar Mantar is an astronomical observatory located in Jaipur, Rajasthan, India. It was built by Maharaja Jai Singh II of Jaipur in 1727. Jantar Mantar is a collection of nineteen architectural astronomical instruments built by Maharaja Jai Singh II of Jaipur, India, between 1727 and 1734. These instruments are used to measure time, altitude, and the position of stars and planets. Jantar Mantar is one of the largest and best-preserved collections of such instruments in the world.
The instruments at Jantar Mantar are made of stone and marble. They are aligned with the cardinal directions and are designed to track the movement of the sun, moon, and stars. The instruments are used to measure time, altitude, and the position of stars and planets.
Jantar Mantar is a popular tourist destination. It is open to the public and is free to visit.
A. Rajasthan is the correct answer because Jantar Mantar is located in Jaipur, Rajasthan, India.
B. Assam is incorrect because Jantar Mantar is not located in Assam.
C. Bihar is incorrect because Jantar Mantar is not located in Bihar.
D. Gujarat is incorrect because Jantar Mantar is not located in Gujarat.