In ancient India Ujjain was famous for the study of:

Correct option is B

In ancient India, Ujjain was renowned for its advancements in the study of astronomy. Ujjain, also known as Avantika, was an important center for astronomical research and education. The city was home to great astronomers like Varahamihira, who was part of the Navaratnas (nine gems) in the court of King Vikramaditya. Varahamihira made significant contributions to astronomy and astrology through his famous works, including the Brihat Samhita and Pancha Siddhantika.
Ujjain's importance as an astronomical hub also stemmed from its geographic location along the Tropic of Cancer, which made it ideal for astronomical observations.
Information Booster: 1. Varahamihira: One of the greatest astronomers of ancient India, who lived and worked in Ujjain.
2. Brihat Samhita: A famous work on astrology and astronomy authored by Varahamihira.
3. Pancha Siddhantika: A treatise that discusses five earlier astronomical texts and theories.
4. Ujjain was an important center for learning and was linked with the development of the Hindu calendar system.
5. Vikram Samvat: The Hindu calendar system originated in Ujjain under King Vikramaditya’s reign.
6. Ujjain's observatory, the Jantar Mantar, built later during the medieval period, also reflects its continued importance in the study of astronomy.