In the two sets given below, set-I specifies level in a water sample, while set – II provides observations. Match the two sets and indicate your answer from the code given below. Set – I (H2S level in water sample) Set – II(Observation)(a) No H2S is produced(i) Dark black – high water pollution(b) H2S is produced and is small in quantity(ii) No colour – clean water(c) H2S is produced and is medium in quantity(iii) Light black – low water pollution(d) H2S is produced and is high in quantity(iv) Black – moderate water pollution

• A. (a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)
• B. (a) - (iv), (b) - (i), (c) - (ii), (d) - (iii)
• C. (a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
• D. (a) - (ii), (b) - (iii), (c) - (iv), (d) - (i)