Yashovarman was ruler of which one of the following kingdoms ?

Yashovarman (c. 725–752 AD) was a powerful and influential monarch who ruled the kingdom of Kannauj (Kanyakubja) in North India during the early 8th century.

• Post-Harsha Era: Following the death of Harshavardhana, North India faced a power vacuum. Yashovarman emerged as a dominant ruler, restoring Kannauj as a major political and cultural center.
• Literary Patronage: He was a great patron of arts and literature. His court was graced by renowned scholars like Bhavabhuti (author of Uttararamacharita) and Vakpatiraja.
• Military Conquests: Vakpatiraja's Prakrit poem, Gaudavaho, describes Yashovarman's extensive military campaigns, most notably his victory over the Gauda king of Bengal.
• Geopolitics: He initially allied with King Lalitaditya Muktapida of Kashmir to counter Arab and Tibetan threats, though they later became rivals for regional supremacy.

Therefore, Option A is the correct answer as his reign is synonymous with the history of Kannauj.