The value of 

$$\sum_{n = 0}^\infty \frac{n_{C_{0}} + n_{C_{1}} + ..... +n_{C_{n}}}{n_{P_{n}}}$$ 

is

A

$$2e - 1$$

B

$$e^2 - 1$$

C

$$e^2 + 1$$

D

$$e^2$$