What A Series

Calculus Level 3

If \(f(x)=(x+1)(x+2)(x+3) \ldots (x+n)\) then what is \(f^{'}(0)\)?

\[1\] n! \[0\] \[n\times{n!}\] \[n!(1+\frac{1}{2}+\frac{1}{3}+.....\frac{1}{n})\] \[-1\] \[(1+\frac{1}{2}+\frac{1}{3}+.....\frac{1}{n})\]