**Core Concept**
Incidence and prevalence are two fundamental measures used in epidemiology to describe the burden of a disease in a population. Incidence represents the number of new cases occurring within a specified time period, while prevalence is the total number of cases (both new and existing) present in the population at a given time.

**Why the Correct Answer is Right**
To calculate the prevalence, we need to consider both the incidence and the duration of the disease. The formula for prevalence is: Prevalence = Incidence x Duration. Given the incidence is 4 per 1000 of the population and the duration is 2 years, we can calculate the prevalence as follows: Prevalence = (4/1000) x 2 = 8 per 1000 of the population.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not take into account the duration of the disease. Without considering the duration, the prevalence would be underestimated.
* **Option B:** This option is incorrect because it incorrectly uses the incidence rate as a percentage, rather than a rate per population.
* **Option C:** This option is incorrect because it incorrectly assumes that the prevalence is equal to the incidence.
* **Option D:** This option is incorrect because it does not provide a clear calculation or formula for the prevalence.

**Clinical Pearl / High-Yield Fact**
When calculating prevalence, it's essential to consider both the incidence and the duration of the disease. A higher duration can lead to a higher prevalence, even if the incidence remains constant.

**Correct Answer:**
Prevalence = 8 per 1000 of the population.