Sodium stearate forms associated colloids

•  At low concentrations, soaps and detergents behave like real solutions, but when they reach the Critical Micelle Concentration (CMC), which is ${10}^{-4}\mathrm{M}$ to ${10}^{-3}\mathrm{M}$, they start to form colloids (tail). 

Hydrophilic (polar) is the ${\mathrm{COO}}^{-}\mathrm{part}\left(\mathrm{head}\right).$ 

When the concentration is low, ${\mathrm{C}}_{17}{\mathrm{H}}_{35}{\mathrm{COO}}^{-}{\mathrm{Na}}^{+}\mathrm{ions}$ are present on the surface, with the ${\mathrm{COO}}^{-}$ groups remaining in the water and the ${\mathrm{C}}_{17}{\mathrm{H}}_{35}$ chains remaining at the surface. Micelles are formed as a result of association above CMC, where the polar part (or) the anion part ${\mathrm{COO}}^{-}$ are drawn into the bulk where they aggregate to form spherical shape with the ${\mathrm{C}}_{17}{\mathrm{H}}_{35}$ part (non-polar) toward the centre of the sphere and ${\mathrm{COO}}^{-}$ part remaining outward on the surface of the sphere.

The anionic component is hydrophilic, whereas the hydrophobic hydrocarbon chain dissolves the grease deposit. 

Hence the correct option is (C).