Consider the following statements in the context of Neolithic Chalcolithic culture.; I. The people of Neolithic Chalcolithic culture used stone implements.; II. The post Harappan sites representing Neolithic-Chalcolithic culture, out number those of pre-Harappan.; III. Some important sites representing this culture are Ahar, Gilund and Balathal. Which of the above statement(s) is/are correct?