Which of the following is a measurement of water pollution?

Step-by-step solution

(a) PSC (polar stratospheric clouds) are special type of clouds formed over Antarctica in winter that play important role in ozone layer depletion. (b) PCB (poly chlorinated biphenyls) are toxic chemicals with high stability and resistance to oxidation. These are used for fluids in transformers and capacitors. (c) BOD (biochemical oxygen demand) is a measure of dissolved oxygen that would be needed by the microorganisms to oxidise organic and inorganic compounds present in polluted water. (d) COD (chemical oxygen d