If $$x = (\frac{a}{b}) + (\frac{b}{a}), y = (\frac{b}{c}) + (\frac{c}{b})$$ and $$z = (\frac{c}{a}) + (\frac{a}{c})$$, then what is the value of $$xyz - x^2 - y^2 - z^2$$?

A

-4

B

2

C

-1

D

-6