**Core Concept**
The coefficient correlation 'r' measures the strength and direction of a linear relationship between two variables X and Y. It is a statistical measure that ranges from -1 to 1, where 1 or -1 indicates a perfect positive or negative linear relationship, and 0 indicates no linear relationship.

**Why the Correct Answer is Right**
When the values of X and Y are multiplied by a constant (in this case, 4), the relationship between the variables remains the same, but the scale of the variables increases. The coefficient correlation 'r' is a dimensionless quantity that is independent of the units of measurement. Therefore, when X and Y are multiplied by 4, the coefficient correlation 'r' remains the same.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because multiplying X and Y by a constant changes the scale of the variables, but not the relationship between them.
* **Option B:** This option is incorrect because the coefficient correlation 'r' is not affected by changes in the scale of the variables.
* **Option C:** This option is incorrect because there is no mathematical operation that would change the coefficient correlation 'r' when X and Y are multiplied by 4.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that statistical measures like correlation coefficient 'r' are scale-independent, meaning they remain unchanged when the units of measurement are altered.

**Correct Answer:** .