**Core Concept**
The range is a measure of variability in a dataset, calculated as the difference between the highest and lowest values. In statistics, it is used to describe the spread of a distribution, and it is an essential concept in medical research and data analysis.

**Why the Correct Answer is Right**
To calculate the range, we need to identify the highest and lowest values in the dataset. The highest value is the maximum value, and the lowest value is the minimum value. The range is then calculated as the difference between the maximum and minimum values. In this case, the maximum value is 10 and the minimum value is 3. Therefore, the range is 10 - 3 = 7.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided in the question.
* **Option B:** This option is also not provided in the question.
* **Option C:** This option is not provided in the question.
* **Option D:** This option is also not provided in the question.

**Clinical Pearl / High-Yield Fact**
When analyzing a dataset, it's essential to consider multiple measures of variability, including the range, mean, median, and standard deviation. These measures can provide different insights into the distribution of the data and can help researchers and clinicians make informed decisions.

**Correct Answer: C. 7**