If $$a + b + c = 0$$ and $$x = y + z$$, then
$$\frac{(x - a)^2}{(y + b)(z + c)} - \frac{(y + b)^2}{(x - a)(z + c)} - \frac{(z + c)^2}{(x - a)(y + b)} =$$

A

1

B

3

C

-3

D

0