I would imagine it would be option E) 6 & 6. if you had a set of 5 numbers (1,2,3,4,5) the mean would be 3, and the standard deviation would be the sqrt of 2, or roughly 1.4. If you added two data points, both equal to the mean, the set would become 1,2,3,3,3,4,5, the mean would be 3 still, but ...