If $\lim\limits_{x\to 0}\large\frac{((a-n)nx-\tan x)\sin nx}{x^2}$$=0$ where $n$ is a non zero real number, then $a$ is equal to

Question

$(a)\;0\qquad(b)\;\large\frac{n+1}{n}$$\qquad(c)\;n\qquad(d)\;n+\large\frac{1}{n}$