A

Explanation:
The correct answer is “A. 2.86.” The standard deviation measures the dispersion of the revenue data points from the mean. The revenue profile data (N20m, N25m, N18m, N24m) is used to compute the standard deviation using the formula for standard deviation, which is the square root of the variance.

Run-down:
Standard deviation is used to quantify the amount of variation or dispersion in a set of values. Here, the values represent the revenues over four years, and the standard deviation of these values is calculated as 2.86.