The derivative of $$f(x) = \frac{x^{3}+3}{x-1}$$

A

$$\frac{(x-1)x-(x^{2} +3)}{(x-1)^{2}}$$

B

$$\frac{(x-1)2x-(x^{2} +3)}{(x-1)^{2}}$$

C

$$\frac{(x+1)x-(x^{2} +3)}{(x-1)^{2}}$$

D

$$\frac{(x-1)2x-(x^{2} -3)}{(x-1)^{2}}$$