$$\frac{1}{\sqrt{5} - 1} - \frac{1}{2 - \sqrt{3}} + \frac{1}{\sqrt{3} - \sqrt{2}} - \frac{1}{\sqrt{2} - 1} + 1 =$$

A

0

B

1

C

$$\sqrt{5}$$

D

$$2 \sqrt{5}$$