If $$f(y) = 1 - (y-1) + (y-1)^2 - (y-1)^3 + \ldots - (y-1)^{17}$$ then the coefficient of $$y^2$$ in it is

A

$${}^{17}C_2$$

B

$${}^{17}C_3$$

C

$${}^{18}C_2$$

D

$${}^{18}C_3$$