## **Core Concept**
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. It is a measure of a country's well-being and quality of life. The HDI is calculated based on three main components.

## **Why the Correct Answer is Right**
The three components of the Human Development Index (HDI) are:
1. **Life expectancy at birth (LE)**: This reflects the health and longevity aspect of a population.
2. **Expected years of schooling (EYS) and Mean years of schooling (MYS)**: These reflect the education aspect.
3. **Gross National Income (GNI) per capita**: This reflects the standard of living or economic prosperity.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incomplete as it does not cover all three components.
- **Option B:** Similarly, this option lacks one of the critical components of HDI.
- **Option D:** This option introduces irrelevant or unspecified components not recognized within the HDI framework.

## **Clinical Pearl / High-Yield Fact**
A key fact to remember is that the HDI provides a broader view of a country's development beyond just economic growth, emphasizing health, education, and income equality.

## **Correct Answer:** . Life expectancy, education, and income.