Explanation:

Correct Option: (b) Explanation:  Statement 3 is incorrect: Sisupalgarh was a well-planned and densely populated settlement. Supplementary notes Sisupalgarh site  The excavation of the Sisupalgarh site was fi rst taken up in 1948, when it was declared a Centrally Protected Monument under the provisions of the Ancient Monuments Preservation Act, 1904, involving an area measuring 562.681 acres and covering fi ve villages, including Sisupalgarh, Badadhanpu Lingipur, Raghunathpur and Mahabhoisasan, in 1950.  Sisupalgarh, believed to have been built around the 7th to 6th century BCE, served as the capital of the Kalinga kingdom, and was an important centre of trade and commerce during ancient times.  The construction of Sisupalgarh was based on the JalaDurga (Water Fort) concept, which in Odia is known as GadaKhai concept.  Jala Durga is a type of durga or fort, which must be situated within a water body, and its access is rendered diffi cult on account of the typical tract. It is divided into two categories, viz., the Anterdvipa (Island fort) and the Sthala Durga (Land fort). Antardvipa-Durga (island fortress) is surrounded by natural (sea or river) water bodies.  Sthala-Durga (plain fortress) is surrounded by arti fi cial moats or irrigated by a river.  This may be assumed that Sisupalgarh was based on Sthala Durga concept, as we can also fi nd remains of River Gandhawati, which is now famous as Gangua nala.