$$\cot (-840^{\circ}) + \cosec (330^{\circ}) + \sec (1020^{\circ}) - \sin (-1320^{\circ}) =$$

A

$$\frac{1}{2\sqrt{3}}$$

B

$$2\sqrt{3}$$

C

$$ -2\sqrt{3}$$

D

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