All the following statements about purification of water are true except
A. Presence of clostridial spores indicate recent contamination
B. Coliforms must not be detectable in any 100ml sample of drinking water
C. Sodium thiosulphate is used to neutralize chlorine
D. Coliforms may be dtected by multiple tube method and indole production at 44 degrees
Please contribute to the discussion by posting the answer with references and pointing out any errors in the question!