## 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 takes into account literacy rate, infant mortality rate, and life expectancy at age one.

## Why the Correct Answer is Right
The PQLI is a composite index that averages three basic indicators: literacy rate (which reflects the education level), infant mortality rate (which reflects health care quality), and life expectancy at age one (which reflects overall health and survival). These indicators are chosen because they are considered to reflect basic aspects of quality of life.

## 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 because it also does not accurately list the components of PQLI.
- **Option D:** This option is incorrect because it does not include all the correct components of PQLI.

## Clinical Pearl / High-Yield Fact
A key point to remember is that PQLI is often used as a broad indicator of a country's well-being and development, particularly in comparisons across different countries. It provides a simple, though somewhat crude, measure that can be used to assess changes over time or differences between countries.

## Correct Answer: C. Literacy rate, infant mortality, and life expectancy at age one.