Option c is the correct answer. Emperor Harsha had shifted his capital from Thaneshwar (now in Haryana) to Kannauj (now in Uttar Pradesh) after he defeated the Maukhari king Avantivarman and annexed his territory. Kannauj was a prosperous and cosmopolitan city that became the center of Harsha's vast empire. It extended from Punjab to Bengal and from Himalayas to Narmada. Kannauj was also the venue of the famous religious assembly that Harsha organized in 643 CE. It was attended by thousands of monks, scholars, and dignitaries from India and abroad.