Human Development Index comprises literacy rates, life expectancy at birth and

The question asks for the components of the Human Development Index (HDI), besides literacy rates and life expectancy at birth.The Human Development Index (HDI), developed by the United Nations Development Programme (UNDP), measures human development based on three key dimensions:1. A long and healthy life (measured by life expectancy at birth).2. Knowledge (measured by mean years of schooling and expected years of schooling; historically, literacy rates were used).3. A decent standard of living (measured by Gross National Income (GNI) per capita, adjusted for purchasing power parity (PPP)).Option (A) GDP per head in US dollars: Incorrect measure and unit.Option (B) Gross Domestic Product per head at real purchasing power: This is close. While GNI per capita (PPP) is the current standard, GDP per capita (PPP) was used in earlier versions of the HDI and reflects the standard of living component adjusted for purchasing power differences.Option (C) Gross National Product in US dollars: Incorrect measure (uses GNP, not adjusted for PPP).Option (D) National Income per head in US dollars: Incorrect measure (uses NI, not adjusted for PPP).Given the options and the historical context (HDI methodology has evolved), GDP per capita at real purchasing power (PPP) is the best fit for the income component besides literacy and life expectancy.