**Core Concept**
The Physical Quality of Life Index (PQLI) is an attempt to measure the quality of life or well-being of a country. The PQLI combines three basic components: literacy rate, infant mortality rate, and life expectancy at age one.

**Why the Correct Answer is Right**
The correct answer is not provided, however, the PQLI is a composite index that includes literacy rate, infant mortality rate, and life expectancy at age one. These components are used to assess the overall well-being of a population.

**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, however, any option that includes a component not related to literacy rate, infant mortality rate, or life expectancy at age one would be incorrect.
**Option B:** Not provided, however, any option that includes a component not related to literacy rate, infant mortality rate, or life expectancy at age one would be incorrect.
**Option C:** Not provided, however, any option that includes a component not related to literacy rate, infant mortality rate, or life expectancy at age one would be incorrect.
**Option D:** Not provided, however, any option that includes a component not related to literacy rate, infant mortality rate, or life expectancy at age one would be incorrect.

**Clinical Pearl / High-Yield Fact**
The PQLI is a useful tool for comparing the quality of life across different countries. It is essential to understand the components of the PQLI to appreciate its significance in public health.

**Correct Answer:** Not provided, however, an example answer could be: **Correct Answer: D. Income**