## **Core Concept**
The question assesses understanding of statistical measures used to describe the dispersion or variability of a dataset. Dispersion measures how spread out the values in a dataset are from their mean value. The simplest measure among the ones listed is being queried.

## **Why the Correct Answer is Right**
The range is considered the simplest measure of dispersion to calculate. It is defined as the difference between the highest and lowest values in a dataset. This measure does not require the calculation of mean or other complex statistical operations, making it straightforward and simple to understand.

## **Why Each Wrong Option is Incorrect**
- **Option B: Standard deviation** is a more complex measure that calculates the average distance of each data point from the mean. It involves squaring differences, averaging them, and then taking the square root, making it more complicated than the range.
- **Option C: Mean deviation** involves calculating the average of the absolute differences from the mean, which, although simpler than standard deviation, still requires more computation than the range.
- **Option D: Co-efficient of range** is a relative measure of dispersion that expresses the range as a ratio of the sum of the highest and lowest values. While it might be simple to calculate once the range is known, it still involves more steps than determining the range itself.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while the range is the simplest measure of dispersion, it can be heavily influenced by outliers (extremely high or low values), making it less reliable for datasets with significant variability.

## **Correct Answer: A. Range**