A system described by the transfer function $$H(s) = \frac{1}{s^3 + as^2 + ks + 3}$$ is stable. The constraints on $$\alpha$$ and $$k$$ are

A

$$\alpha > 0, \alpha k < 3$$

B

$$\alpha > 0, \alpha k > 3$$

C

$$\alpha > 0, \alpha k > 0$$

D

$$\alpha > 0, \alpha k < 0$$