The middle term in the expansion $(1+x)^{2n}$ is ?

Question

$\begin{array}{1 1} \large\frac{(2n)!}{n!}.x^n \\ \large\frac{(2n)!}{n!.(n-1)!}.x^{n+1} \\ \large\frac{(2n)!}{n!^2}.x^n \\ \large\frac{(2n)!}{(n+1)!.(n-1)!}.x^n \end{array}$