In which of the following states has India set up the world's first liquid-mirror telescope for astronomy?

Correct option is D

The correct answer is (D) Uttarakhand.

India has set up the world's first liquid-mirror telescope for astronomy in Uttarakhand. The telescope, located at the Devasthal Observatory in Nainital, Uttarakhand, uses a liquid mirror (made of mercury) for observing celestial objects, which is an innovative approach in the field of astronomy.

1. The liquid-mirror telescope is unique because it uses a liquid mercury mirror to reflect light from celestial bodies, making it different from traditional telescopes.

2. The observatory is positioned at a high altitude, offering an optimal environment for astronomical research.

3. It is part of India's growing efforts in space science and research.