Concept:Charcoal is added as activated carbon to adsorb dissolved substances that cause bad taste and odour in water.
Explanation:Township water treatment usually involves filtration through layers of sand and gravel to remove solid particles.
However, dissolved organic impurities, chlorine by-products, and some chemicals can remain even after filtration.
When charcoal is added to the filter bed, its porous surface traps these unwanted molecules through a process called adsorption.
This improves the aesthetic quality of the water by eliminating offensive smells and unpleasant tastes.
It does not kill disease-causing organisms, because disinfection is typically done with chlorine.
Similarly, goiter prevention requires iodine, and tooth decay prevention requires fluoride, neither of which is supplied by charcoal.
Answer:C. remove odour.