The set of all $$\alpha$$, for which the vectors $$\vec{a} = \alpha t\hat{i} + 6\hat{j} - 3\hat{k}$$ and $$\vec{b} = t\hat{i} - 2\hat{j} - 2\alpha t\hat{k}$$ are inclined at an obtuse angle for all $$t \in \mathbb{R}$$, is

A

$$\left(-\frac{4}{3}, 1\right)$$

B

$$[0, 1)$$

C

$$\left(-\frac{4}{3}, 0\right]$$

D

$$(-2, 0]$$