This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pediatrics
[{'content': 'In haemorrhagic disease of newborn which of the following is prolonged \nSelect and explain. \nA. PT, B. aPTT, C. TT, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A prolonged aPTT result may indicate the following : Congenital deficiencies of intrinsic system clotting factors such as factors VIII, IX, XI, and XII, including hemophilia A and hemophilia B (Christmas disease), two inherited bleeding disorders resulting from a deficiency in factors VIII and IX, respectively. Reference: GHAI Essential pediatrics, 8th edition', 'role': 'assistant'}]