Length of each edge of a regular tetrahedron is 1 cm. Its volume is:

A

$$\frac{1}{4}\sqrt{3}\ $$cu.cm

B

$$\frac{\sqrt{2}}{6}\ $$cu.cm

C

$$\frac{1}{12}\sqrt{2}\ $$cu.cm

D

$$\frac{\sqrt{3}}{12}\ $$cu.cm