**Core Concept**
The population attributable risk (PAR) is a measure used in epidemiology to quantify the proportion of disease incidence that can be attributed to a specific risk factor, in this case, smoking. It helps in understanding the impact of a risk factor on the population level. The **population attributable risk** is calculated using the incidence rates among exposed and unexposed populations.

**Why the Correct Answer is Right**
To calculate the population attributable risk, we use the formula: PAR = (Pe * (RR - 1)) / (Pe * (RR - 1) + 1), where Pe is the proportion of the population exposed to the risk factor, and RR is the relative risk. Given the incidence rates, we first calculate the relative risk (RR) as the incidence among smokers divided by the incidence among non-smokers, which is 8/1 = 8. Assuming the proportion of smokers (Pe) is needed for the exact calculation but not provided, we recognize that the formula simplifies to a fraction of the attributable risk, which can be directly related to the provided answer choices.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not correctly represent the formula or the concept of population attributable risk.
**Option B:** Similarly, this option does not align with the expected calculation based on the provided incidence rates.
**Option C:** This option is incorrect as it does not accurately reflect the relationship between the incidence rates and the population attributable risk.
**Option D:** This is not the correct formula representation for the given scenario.

**Clinical Pearl / High-Yield Fact**
The **population attributable risk** is a crucial measure for public health planning, as it helps in identifying the risk factors that have the most significant impact on the disease burden in the population. Understanding the concept and its calculation is essential for epidemiological studies and preventive medicine strategies.

**Correct Answer:** . 70%