If $$\mid x \mid < 1$$ and $$f(x) = 1 + x + x^2 + .......$$ then $$f^{-1}(x) =$$

A

$$\frac{x + 1}{x}$$

B

$$\frac{x}{x + 1}$$

C

$$\frac{x - 1}{x}$$

D

$$\frac{x}{x - 1}$$