One cannot see Fog because?

Question

1. fog absorbs light

2. light is scattered by the droplets in the fog

3. light suffers total reflection by the droplets in the fog

4. the refractive index of the fog is infinity

Answer 1

I'll go for a number 2

Answer 2

The answer is two. Basically what happens the droplets are so packed that it scatters over and over again.

Answer 3

I've never had any problem seeing fog, so I presume you mean "One cannot see _through_ fog because?"  In that case, the answer is 2 - the light is scattered as it hits the droplets in the fog, thereby obscuring your view of anything beyond it.