This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Intrinsic discolouration of teeth which have not originated from developmental defects of the enamel and dentin: 
Select and explain. 
A. Amelogenesis imperfecta., B. Dentinogenesis imperfecta., C. Erythroblastosis fetalis., D. None.
C: Erythroblastosis fetalis.
Answer: C: Erythroblastosis fetalis. 
Explanation: Intrinsic discolorations such as those occurring with amelogenesis imperfecta or dentinogenesis
Imperfecta are impossible to eliminate because they originate from developmental defects of the enamel and dentin. Hematological disorders such as erythroblastosis fetalis, thalassemia, and sickle cell anemia might also be caused due to intrinsic discoloration.