The correct answer is infrastructure.
The Human Development Index (HDI) is a composite statistic of life expectancy, education, and per capita income indicators, which are used to rank countries into four tiers of human development. A country scores higher if it performs better on these indicators.
Life expectancy is a measure of the average number of years that a newborn is expected to live if current mortality rates continue to apply. Education is measured by two indicators: mean years of schooling and expected years of schooling. Per capita income is measured by gross national income (GNI) per capita, which is the total GNI of a country’s economy divided by its population.
Infrastructure is not one of the dimensions used to calculate the HDI. However, it is an important factor in human development, as it can affect access to education, healthcare, and other essential services.