Milk is an example of:

Correct answer: (d) Emulsion

Explanation

Milk is an emulsion – a colloid of two immiscible liquids, with fat globules dispersed in water.

The protein casein acts as the emulsifying agent, stabilising the dispersed fat droplets.

Distinguish: a sol is solid-in-liquid, an aerosol is liquid/solid-in-gas, and a foam is gas-in-liquid.