## Core Concept
The Physical Quality of Life Index (PQLI) is an attempt to measure the quality of life or well-being of a country. It is a composite index that averages three basic literacy, infant mortality, and life expectancy at age one.

## Why the Correct Answer is Right
The PQLI is specifically designed to provide a more accurate and straightforward measure of a country's well-being, particularly in developing nations where traditional economic measures like GDP might not fully capture the quality of life. It focuses on literacy rate, infant mortality rate, and life expectancy at age one, making it a valuable tool for comparing the well-being of different countries.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it does not accurately represent the components of PQLI.
- **Option B:** This option is incorrect as it likely includes indicators not part of the PQLI or misses key components.
- **Option C:** This option is incorrect because it does not correctly list the three components that make up the PQLI.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the PQLI provides a more nuanced view of a country's development by focusing on basic needs and outcomes rather than purely economic metrics. This index is especially useful in comparing the quality of life across different countries, particularly in contexts where economic data might be limited or misleading.

## Correct Answer: D. Literacy, Infant Mortality, Life Expectancy at Age One.