$$OABC$$ is a regular tetrahedron, each side of which is made of uniform wire of resistance $$4\ \Omega\text{ m}^{-1}$$. The length of each side is $$2\ \text{m}$$. The point $$M$$ is the midpoint of the side $$BC$$. The resistance between $$O$$ and $$M$$ is

A

$$5\ \Omega$$

B

$$4\ \Omega$$

C

$$10\ \Omega$$

D

$$15\ \Omega$$