The correct option is C Methaemoglobin
Blue baby syndrome is used to describe new born with cyanotic conditions. It is a pathological condition in which blood’s capacity for oxygen transport is reduced, resulting in bluish skin in infants. Blue baby syndrome beings when large amounts of nitrates in water are ingested by an infant and converted to nitrite by the digestive system. The nitrite then reacts with oxyhaemoglobin (the oxygen-carrying blood protein to form methaemoglobin, which cannot carry oxygen)