You must have heard of the term "HDI", which measure and rank countries' levels of social and economic development. According to you, what is the full form of HDI?

Human Development Index

The Human Development Index (HDI) is a tool developed by the United Nations to measure and rank countries' levels of social and economic development. It measures the life expectancy, education (mean years of schooling completed and expected years of schooling upon entering the education system), and per capita income indicators.