If \( f(x)=\frac{6 x\left(x^{2}+1\right)}{x^{2}+\left(x^{2}+1\right)^{2}}, x \geq 0 \) then subset of range of \( f(x) \) is/are
(A) \( [0,2] \)
(B) \( \left[1, \frac{12}{5}\right] \)
(C) \( \left[\frac{12}{5}, \infty\right) \cup\{0\} \)
(D) \( \left[0, \frac{12}{5}\right] \)
