Correct Answer - Option 3 : 7.8%

__Concept:__

Water content formula is given by:

w = Ww/Ws

where,

w = Water content

Ww = Weight of water

Ws = Weight of solids

__Calculation:__

Given data:

Weight of water (W_{w}) = 2.16 gm

Weight of dry soil or weight of solid (W_{s}) = 27.63 gm

So, Water content, w = \(2.16 \over 27.63\) = 0.0781

Water content (w) = 7.81%