Answer: e) sand filtering and use of activated charcoal
Explanation: The technique used for the filtration of the minute particle from water is done by activated charcoal and sand filtering technique.
Activated charcoal is the considered as good material for the purification of water and helps in removing the toxic particles. Adsorption process is the property on which the purification works.
Sand filtration also a purification process of water . It is done mostly due to the porous nature of sand which traps the toxic minute particles . It is usually done for treating the groundwater.