Let ABC be a triangle such that $$\angle ACB = \frac{\pi}{6}$$ and let a, b and c denote the lengths of the sides opposite to A, B and C respectively. The value(s) of x for which $$a = x^2 + x + 1, b = x^2 - 1$$ and $$c = 2x + 1$$ is (are)

A

$$-(2 + \sqrt{3})$$

B

$$(1 + \sqrt{3})$$

C

$$(2 + \sqrt{3})$$

D

$$4\sqrt{3}$$