If x,y,z are three numbers such that $$x+y=13,y+z=15$$ and $$z+x=16$$, the
value of $$\frac{xy+xz}{xyz}$$ is:

A

$$\frac{5}{36}$$

B

$$\frac{36}{5}$$

C

$$\frac{18}{5}$$

D

$$\frac{5}{18}$$