The correct answer is: Chirand.
Chirand is an archaeological site located in the Saran district of Bihar, India. It is a prehistoric site that has been dated to the Chalcolithic period (3300-1300 BCE). The site is known for its evidence of copper smelting, which is one of the earliest known examples of this technology in the world.
The copper smelting evidence at Chirand consists of slag heaps, crucibles, and tuyeres. The slag heaps are the remains of the ore that was smelted, and the crucibles are the vessels in which the ore was melted. The tuyeres are the pipes that were used to blow air into the furnace to create the heat necessary for smelting.
The copper smelting evidence at Chirand is significant because it provides evidence of the early development of metallurgy in India. It also shows that the people of Chirand were skilled in the use of copper, which was a valuable material in the prehistoric period.
The other options are incorrect because they are not archaeological sites in Bihar that have evidence of copper smelting. Senuwar is a site in the Rohtas district of Bihar, Taradih is a site in the Gaya district of Bihar, and Koldihwa is a site in the Palamu district of Jharkhand. These sites are all important archaeological sites, but they do not have evidence of copper smelting.