The correct answer is option 3 - Purandar. The treaty of Purandar was signed in 1665 between Shivaji, the Maratha king, and Jai Singh, the Mughal emperor Aurangzeb`s general. As per the treaty, Shivaji agreed to surrender 23 of his forts to the Mughals, including important ones like Sinhagad, Raigad, and Purandar, in exchange for peace and to avoid further conflict. Shivaji was initially imprisoned by the Mughals after the signing of the treaty but managed to escape. The treaty of Purandar was significant as it marked a temporary truce between the Marathas and the Mughals, although hostilities resumed later. So, Shivaji ceded the forts to the Mughals by the treaty of Purandar.