All of the following statements about purification of water are true except: (A) Sodium thiosulphate is used to neutralize certain contaminants, (B) Coliforms must not be detectable in any 100 ml sample of drinking water, (C) Presence of Clostridial spores indicates recent contamination of water, (D) Coliforms may be detected by multiple tube method and indole production
Answer is C. None