Which one of the following is wrong statement?
(a) Anabaena and Nostoc are capable of fixing nitrogen in free-living state also
(b) Root nodule forming nirogen fixers live as aerobes under free-living conditions
(c) Phosphorus is a constituent of cell membranes, certain nucleic acids and all proteins
(d) Nitrosomonas and Nitrobacter are chemoautotrophs
(c) Phosphorus is a component of DNA and RNA but not proteins.