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

The HDI combines three dimensions: health (life expectancy at birth), education (historically measured by literacy/years of schooling) and a standard of living measured by an income per capita converted to purchasing power parity. UNDP technical notes specify the income component as GNI per capita in PPP dollars to reflect living standards across countries [2]. Related data sources and summaries also report GDP/GNI per capita in PPP terms when comparing countries’ welfare levels, so the option referring to per-head income at real purchasing power (PPP) is the best match among the given choices [3]. Thus option 2 (GDP per head at real purchasing power) most closely reflects the HDI income concept.

Sources

1. [1] https://hdr.undp.org/sites/default/files/data/2020/hdr2020_technical_notes.pdf
2. [2] https://hdr.undp.org/data-center/human-development-index
3. [3] Contemporary World Politics, Textbook in political science for Class XII (NCERT 2025 ed.) > Chapter 3: Contemporary South Asia > Overview > p. 31