The correct answer is D) gross national income.
The concept that is not a factor the index uses is gross national income.
Every year, the United Nations Development Program rates a nation’s development according to the Human Development Index (HDI). The HDI measures the overall quality of life in a country based on certain factors.
The HDI considers that people and their capabilities are the correct criteria to asses the growth of a nation. It believes that the analysis should not be limited only to economic growth. So HDI considers the dimensions of "Long and healthy life," "A decent standard of living," and "Knowledge," that is per-capita income.