The coefficient of xn in the expansion of (1 - 2x + 3x2 - 4x3 + ... to ∞)-n is

• A. \(\dfrac{(2n)!}{n!(n-1)!}\)
• B. \(\dfrac{(2n)!}{[(n-1)!]^2}\)
• C. \(\dfrac{(2n)!}{(n!)^2}\)
• D. none of these