What is the value of $$(cosec 60^\circ - \frac{1}{2})$$

A

$$\frac{(4-\sqrt{3})}{2\sqrt{3}}$$

B

$$\frac{(2\sqrt{3}-1)}{\sqrt{3}}$$

C

$$\frac{(3\sqrt{3}-1)}{3}$$

D

$$\frac{1}{\sqrt{3}}$$