The correct answer is: B) Copper and stone tools.
The Chalcolithic period, also known as the Copper Age, is a period in human history that followed the Neolithic period and preceded the Bronze Age. It is characterized by the development of copper metallurgy and the use of copper tools and weapons. Copper is a relatively soft metal, so it was often used in combination with stone tools.
Option A is incorrect because the Chalcolithic period is characterized by the use of copper tools, not stone tools only.
Option C is incorrect because the Chalcolithic period is characterized by the use of copper tools, not iron tools.
Option D is incorrect because the Chalcolithic period is characterized by the use of copper tools, not bronze tools. Bronze is an alloy of copper and tin, and it was not developed until the Bronze Age.