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: Pathology
A 9 year old boy with elevation in both PT and A PTT. What is the diagnosis? 
Select and explain. 
A. Defect in extrinsic pathway, B. Defect in intrinsic pathway, C. Platelet function defect, D. Defect in common pathway
D: Defect in common pathway
Answer: D: Defect in common pathway 
Explanation: Ans. is 'd' i.e., Defect in common pathway Defective coagulation pathway PT AM Extrinsic Increased Normal Intrinsic Normal Increased Common Increased Increased