Solution:Jhum, also known as shifting cultivation, is a traditional agricultural practice where people cut down the vegetation of an area, burned them, and then starts farming on this land. This method is predominantly practiced in the north-eastern states of India.Option 1: Manipur does have an area under Jhum cultivation, but it's not more than 50% of the state's total area. Therefore, the answer provided is incorrect.
Option 2: In Assam, Jhum cultivation was practiced primarily in hilly terrains but it doesn't account for 50% of the state's total area.
Option 3: In Sikkim, due to the terrain and climatic conditions, the area under Jhum cultivation isn't significant.
Option 4: Mizoram is the state where over half of the total area is under Jhum cultivation. The steep slopes of the hills and the tribal population's dependency on agriculture contribute to this. Alert - the correct answer should be 4, Mizoram.