If $$\frac{1}{y- x}, \frac{1}{2y}$$ and $$\frac{1}{y- z}$$ are in Arithmetic Progression, then the relation between x, y and z is given by

A

$$y^2 = xz$$

B

$$x + y = 2y$$

C

$$2y = x + z$$

D

$$2z = x + y$$