If three positive real numbers x, y and z satisfy y - x = z - y and xyz = 4, then what is the minimum possible value of y?

- 2
^{(1/4)} - 2
^{(2/3)} - 2
^{(1/3)} - 2
^{(3/4)}

**Answer**

y - x = z - y

2y = x + z

Therefore, x, y, z are in Arithmetic Progression

AM ≥ GM

(x+y+z)/3 ≥ (xyz)^{1/3}

y ≥ 2^{(2/3)}

**The correct option is B.**