The correct answer is: a) Vangchhia.
Vangchhia is an important archaeological site with megaliths and cave carvings. It is located in the state of Mizoram in India. The site is believed to be over 2,000 years old and contains a number of megalithic structures, including stone circles, dolmens, and menhirs. The cave carvings at Vangchhia depict a variety of scenes, including hunting, dancing, and religious ceremonies.
The other options are incorrect. Kolasib is a town in the state of Mizoram. Phawngpui is a mountain in the state of Mizoram. Champai is a district in the state of Mizoram.
Vangchhia is an important archaeological site because it provides valuable insights into the history and culture of the people who lived in the region over 2,000 years ago. The site is also a popular tourist destination.