If $$p = \frac{a-b}{a+b}, q = \frac{b-c}{b+c}, r = \frac{c-a}{c+a}$$, then $$\frac{1+p}{1-p}, \frac{1+q}{1-q}, \frac{1+r}{1-r}$$ =

A

1

B

2

C

3

D

4