Option b is the correct answer. The information regarding the time of Harsha is contained in the book written by Kalhana. Kalhana was a Kashmiri historian and poet who authored the "Rajatarangini," a historical chronicle of the kings of Kashmir. The Rajatarangini provides valuable historical information about the reign of Harsha and other rulers. Important Tips Facts about Rajatarangini: The Rajatarangini is considered as one of the earliest and most reliable sources of Indian history. It covers the period from the mythical origins of Kashmir to the 12th century CE, when Kalhana lived. The Rajatarangini is written in Sanskrit verse and consists of eight chapters, each containing a genealogy and a narrative of a dynasty. It mentions several important events and personalities that shaped the Indian subcontinent, such as the invasions of Alexander the Great, the Kushanas, the Hunas, and the Arabs; the rise and fall of the Mauryas, the Guptas, the Harshavardhana, and the Palas; and the achievements of Ashoka, Chandragupta II, Kumaragupta I, Skandagupta, Lalitaditya Muktapida, Jayapida, and Avantivarman.