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: Gynaecology & Obstetrics
Which is abnormal in classic hemorrhagic disease of newborn ? 
Select and explain. 
A. Platelet count, B. Thrombin time, C. Fibrinogen level, D. APTT
B: Thrombin time
Answer: B: Thrombin time 
Explanation: Thrombin time