$^nC_0^2$ + $^nC_1^2$ + $^nC_2^2$ + ...... + $^nC_n^2$ = ?

Question

$\begin{array}{1 1} n.^{2n}C_n \\ (n+1).^nC_n^2 \\ n.^nC_2^2 \\ ^{2n}C_n \end{array}$