If $$x = \left(\frac{a + b}{a - b}\right), y = \left(\frac{b + c}{b - c}\right), z = \left(\frac{a + c}{c - a}\right)$$ and $$a \neq b \neq c$$ then$$\left(\frac{1 - x}{1 + x}\right) \left(\frac{1 - y}{1 + y}\right) \left(\frac{1 - z}{1 + z}\right) = $$

A

2

B

+1

C

-1

D

-2