Find the mean proportional of squares of $$\frac{x}{y}$$ and $$\frac{y}{z}$$

A

$$\left(\frac{X}{Z}\right)^{3/2}$$

B

$$\sqrt{\frac{X}{Z}}$$

C

$$\frac{X}{Z}$$

D

$$\left(\frac{X}{Z}\right)^{2}$$