If d is the standard deviation x, y, and z, what is the standard deviation of x +7, y + 7, z + 7 ?	Choose the correct option.
A) 7d B) 7d+7 C) 7d+14 D) d E) 7d+21
CONCEPT: Standard Deviation is Defined as Average Deviation of Terms in the set from the Mean value of the set. i.e.   1) It depends on the separation between the successive terms of the set   2) If a Constant Value is Added/Subtracted in every terms of set then the Separation between successive terms does NOT change Hence S.D. remains Constant   e.g.{1, 2, 3, 4, 5} will have same standard Deviation as {1+10, 2+10, 3+10, 4+10, 5+10}   3) If a Constant Value is Multiplied in every terms then the Separation between succesive terms gets multiplied by the constant Hence S.D. remains gets multiplied by same Number   e.g. {0.7, 1.4, 2.1, 2.8, 3.5} will have Standard Deviation = 0.7* Standard deviation of set {1, 2, 3, 4, 5}   When 7 is added in each term of set {x, y, z} then the new set {x+7, y+7, z+7} will remain same as the previous standard deviation i.e. d   Answer: d
<result>D</result>
If d is the standard deviation x, y, and z, what is the standard deviation of x +7, y + 7, z + 7 ?