Let $f:R\rightarrow R$ be defined by $f(x)=3x^2-5\; and \;g:R\rightarrow R \;by \;g(x)=\Large {\frac{x}{x^2+1}}$.Then g o f is

Question

$$\begin{array}{1 1}(A)\;\frac{3x^2-5}{9x^4-30x^2+26} & (B)\;\frac{3x^2-5}{9x^4-6x^2+26}\\(C)\;\;\frac{3x^2}{x^4+2x^2-4} & (D)\;\frac{3x^2}{9x^4-30x^2-2}\end{array}$$