GMAT Question of the Day – PS – Standard Deviation

Which of the following sets has the same standard deviation as the set that contains k, k + 2, and 2k?

A. k-2, -2, 0

B. 2k, 2k + 4, 4k

C. 1, 2, k

D. k, k-1, k-2

E. k/2, k, 2

[spoiler]A.[/spoiler]