## **Core Concept**
The dependency ratio is a demographic measure that calculates the proportion of dependents (people who are either too young or too old to work) in a population compared to the working-age population. It is expressed as a ratio or percentage and is used to assess the economic burden on the working population. The dependents are typically considered to be those under the age of 15 (children) and those aged 65 and over (the elderly).

## **Why the Correct Answer is Right**
The correct answer, **C. (0-14, 65 and above) / (15-64)**, is right because it accurately represents the formula for calculating the dependency ratio. This ratio includes children (ages 0-14) and the elderly (ages 65 and above) as dependents and compares them to the working-age population (ages 15-64). This calculation helps in understanding the support burden on the working population.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify the age groups correctly associated with the dependency ratio.
- **Option B:** This option is incorrect because, although it mentions relevant age groups, it does not accurately represent the formula for the dependency ratio.

## **Clinical Pearl / High-Yield Fact**
A high dependency ratio can indicate a greater burden on the working population to support the dependents, potentially affecting economic growth and social security systems. Conversely, a low dependency ratio may suggest a more favorable economic situation but can also indicate an aging population with a shrinking workforce.

## **Correct Answer:** .