Answer:
c . milk
Explanation:
Colloid are those whose particles are larger than the size of molecule.The size of particle is one nano meter.Collide particle range is between 1 to 1,000 nano meter. Every collide particle is consist of two parts colloidal particle and dispersion medium.
Milk is one of them.Collide are made form solid liquid and gas.
milk is the example of liquid collide.
Petrochemicals include many things, I would say All of the above. Hope this helped! :)