$$\tan 480^\circ + \sec 510^\circ + \cosec 750^\circ + \cot 765^\circ =$$

A

$$3 - \sqrt{3}$$

B

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

C

$$3 - \frac{5}{\sqrt{3}}$$

D

$$2 - \frac{5}{\sqrt{3}}$$