The correct answer is: Stone.
Prehistoric tools and artifacts found in Chhattisgarh are often made of stone. This is because stone is a durable material that can withstand the elements for long periods of time. It is also a relatively easy material to work with, which makes it ideal for creating tools and other objects.
Plastic, gold, and paper are not as common materials for prehistoric tools and artifacts. Plastic is a relatively new material, and it was not widely available until the 20th century. Gold is a valuable material, and it is likely that any gold objects that were created in prehistoric times would have been melted down and reused. Paper is also a relatively new material, and it was not widely available until the 1st century AD.
Therefore, the most likely material for prehistoric tools and artifacts found in Chhattisgarh is stone.