Find Three Positive Numbers X, Y, and Z Whose Sum $x = 10 , y = 10 , z = 10$

Multiple Choice

Find three positive numbers x, y, and z whose sum is 30 and the sum of the squares is a minimum.

A) $x = 10 , y = 10 , z = 10$
B) $x = 2 , y = 12 , z = 16$
C) $x = 7.5 , y = 7.5 , z = 15$
D) $x = 4 , y = 6 , z = 10$
E) $x = 5 , y = 5 , z = 20$