Explanation:

- Correct Answer: Option 1 - Udaipur

- The Solar Observatory in Rajasthan is indeed located in Udaipur.

- This observatory is known for solar research and studies sunspots, solar flares, and other solar activities.

- Option 2 - Jaipur

- Jaipur is a major city in Rajasthan, famous for its rich history and architecture.

- It hosts observatories like Jantar Mantar but is not home to the solar observatory.

- Option 3 - Ajmer

- Ajmer is known for its cultural heritage, including the famous Ajmer Sharif Dargah.

- It is not associated with a solar observatory.

- Option 4 - Jodhpur

- Jodhpur is known for its stunning palaces and the Mehrangarh Fort.

- There is no solar observatory located here.