Hint:Boot polish is a colloid solution. Colloid solutions are mixtures in which microscopically dispersed insoluble particles of one substance are suspended in another substance. Size of the particles in a colloid can range $1nm - 1000nm.$ Colloidal particles cannot be seen by naked eye but can be seen through a microscope.
Complete step by step answer:
Colloid solutions are classified on the basis of dispersed phase and dispersion medium. The dispersed phase is a phase that is present in the form of colloid particles called the dispersed phase. The medium in which the colloid particles are dispersed is called the dispersion medium. In boot polish dispersed phase is liquid and the dispersion medium is solid. This type of combination is called Gel.
Thus the Boot polish contains liquid dispersed phase in solid dispersion medium. So, the correct option is $A$ .
Additional information:
Table summarizes the type of colloid solution on the basis of dispersed phase and dispersion medium
| Type of colloid solution | Dispersed Phase | Dispersed Medium | Examples |
| Smoke (aerosol) | Solid | Gas | Dust, soot in air |
| Sol | Solid | Liquid | Ink, Colloidal gold |
| Solid sol | Solid | Solid | Ruby glass and alloy |
| Liquid aerosol | Liquid | Gas | Fog and clouds |
| Emulsion | Liquid | Liquid | Milk and hair cream |
| Gel | Liquid | Solid | Butter and cheese |
| Foam | Gas | liquid | Whipped cream and shaving cream |
| Solid foam | Gas | Solid | Cork, pumice stone |
Note:
As we see in above table there is no combination of gas dispersed phase and gas dispersed medium as in the case solid in solid and liquid in liquid because gas in gas form a hom*ogeneous solution which is not a colloid solution. Colloids solutions are heterogeneous mixtures.
