## Core Concept
Mortality measurements are crucial in epidemiology to understand the impact of diseases on populations. These measurements help in assessing the severity and outcome of diseases. Common mortality measurements include crude death rate, case fatality rate, and proportional mortality.

## Why the Correct Answer is Right
The correct answer, , refers to the proportion of deaths within a specified population due to a particular cause. This is a measure of mortality but specifically focuses on the distribution of causes of death rather than the rate or risk of death.

## Why Each Wrong Option is Incorrect
* **Option A:** - This option likely refers to a rate or ratio that directly measures mortality, such as the crude death rate (total deaths per 1,000 people per year) or the case fatality rate (deaths due to a disease divided by the number of cases of that disease).
* **Option B:** - Similar to Option A, this would represent another form of mortality measurement, possibly focusing on the risk of death within a specified timeframe.
* **Option D:** - This option would also represent a measurement related to mortality, such as mortality rate or survival rate.

## Clinical Pearl / High-Yield Fact
A key point to remember is that while mortality rates (like case fatality rate) and ratios (like proportional mortality) are both used to understand disease outcomes, they measure different aspects. For instance, the **case fatality rate** is a direct measure of severity, whereas **proportional mortality** gives insight into the burden of different causes of death within a population.

## Correct Answer: .