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: Pediatrics
Anti-A, anti-B, antibody appear in child ? 
Select and explain. 
A. Just after bih, B. 1 week after, C. 6 week after, D. After 6 months
D: After 6 months
Answer: D: After 6 months 
Explanation: Ans. is 'd' i.e., After 6 months Titre of anti-A and anti-B antibodies is almost zero immedietly after bih. Infants sta producing anti-A and anti-B antibodies at age of 2-8 month when corresponding antigen is not present in cell. Maximum titre rech at 8 to 10 years of age after that it staed declinning.