As of 2010, the least-developed country in the world was
D.
Botswana
Explanation:
After Decolonization he worst area in the world in terms of poverty had been sub Saharan Africa that had been constantly under the world in terms of Human Development and Poverty.
This is because of the failure of those states after being crippled by colonization and then not being able to form stable governments.
This is one of the prime reasons for Botswana which was the poorest nation in the world and the least developed in 2010 with the lowest HDI rating of all nations.
