Option a is the correct answer. Kannauj was the main business centre during the postGupta period. It spanned from the 6th to the 8th century CE. Kannauj was the capital of several powerful dynasties, such as the Maukharis, the Later Guptas, and the Harshavardhana. Kannauj was a prosperous and cosmopolitan city that had a flourishing trade with various regions of India and abroad. Kannauj was famous for its production and export of perfumes, textiles, jewels, and spices. Important Tips Facts about business center during various histrocial period: Dhar was a major business center during the Early Medieval period. It was in western India, and it was the capital of the Gurjara-Pratihara dynasty. The city was also home to a number of industries, such as textiles and metalworking. Devgiri was a major business center during the Later Medieval period. It was in western India, and it was the capital of the Yadava dynasty. The city was also home to several industries, such as textiles and metalworking. Ujjain was another important business center during the Post-Gupta period, not as large as Kannauj. It was in central India and it was a major religious and cultural center. The city was also home to a number of industries, such as textiles and metalworking.