In which state of the Indian Union, the government encouraged a private militia (Salva Judum) and whose action was invalidated by the Supreme Court?

The correct answer is B. Chhattisgarh.

The Salwa Judum was a civilian militia formed in 2005 by the government of Chhattisgarh to fight the Naxalite insurgency in the state. The militia was accused of human rights abuses, including extrajudicial killings, torture, and forced displacement. In 2011, the Supreme Court of India invalidated the Salwa Judum, calling it “unconstitutional and illegal.”

The other options are incorrect. Orissa (Odisha) is a state in eastern India. Madhya Pradesh is a state in central India. West Bengal is a state in eastern India.