A sample of $500\:g$ dry sand, when poured into a $2$ litre capacity cylinder which is partially filled with water, displaces $188\:cm^3$ of water. The density of water is $1\:g/cm^3.$ The specific gravity of the sand is
1. $2.72$
2. $2.66$
3. $2.55$
4. $2.52$