The correct option is C the Rh- mother is sensitized to the Rh+ antigen and the baby is Rh+
Erythroblastosis foetalis can result if the Rh- mother is sensitized to the Rh+ antigen and the baby is Rh+. In the first pregnancy, Rh antigens of the foetus do not get exposed to the Rh-ve blood of the mother as the two bloods are well separated by the placenta. However, during the delivery of the first
child, there is a possibility of exposure of the maternal blood to small amounts of the Rh+ve blood from the foetus. In such cases, the mother starts preparing antibodies against Rh in her blood and in the subsequent pregnancies, the Rh antibodies from the mother (Rh-ve) can leak into the blood of the foetus (Rh+ve) and destroy the foetal RBCs. This condition is called erythroblastosis foetalis.