**Core Concept**
A positive mortality indicator is a statistical measure used to identify factors or conditions associated with an increased risk of death. In public health and clinical epidemiology, these indicators help in understanding the burden of disease, identifying high-risk populations, and informing healthcare policies. Positive mortality indicators can be based on various factors such as age, sex, socioeconomic status, or specific comorbid conditions.

**Why the Correct Answer is Right**
The correct answer is **Proportional Mortality Ratio (PMR)**. The PMR is a widely used positive mortality indicator that measures the proportion of deaths due to a specific cause within a population. It is calculated by dividing the number of deaths due to a particular cause by the total number of deaths from all causes, multiplied by 100. For example, if the PMR for cardiovascular disease is 25%, it means that 25% of all deaths in the population are due to cardiovascular disease. The PMR is an important tool in identifying the leading causes of death and guiding public health interventions.

**Why Each Wrong Option is Incorrect**
**Option A:** **Case Fatality Rate (CFR)** is a negative mortality indicator, which measures the proportion of individuals with a specific disease who die from that disease. It is the inverse of a positive mortality indicator like PMR.

**Option B:** **Mortality Rate** is a general term that refers to the number of deaths per unit population over a specified period. While it is a useful measure, it does not specifically identify the causes of death.

**Option C:** **Standardized Mortality Ratio (SMR)** is a measure of the number of deaths that occur in a population compared to a standard population. While it can be used to identify differences in mortality rates between populations, it is not a positive mortality indicator in the same sense as PMR.

**Clinical Pearl / High-Yield Fact**
When analyzing mortality data, remember that PMR is a useful tool for identifying the leading causes of death, but it may not accurately reflect the actual burden of disease if there are differences in mortality rates between populations.

**Correct Answer: D. Proportional Mortality Ratio (PMR)**