If $S_r=\begin{vmatrix}2r&x&n(n+1)\\6r^2-1&y&n^2(2n+3)\\4r^32nr&z&n^3(n+1)\end{vmatrix}$ then value of $\sum\limits_{r=1}^n S_r$ is independent of

Question

$\begin{array}{1 1}(A)\;\text{x only}&(B)\;\text{y only}\\(C)\;\text{x,y,z,n }&(D)\;\text{n only}\end{array}$