This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2017, Subject name: Pathology
In a platelet poor plasma sample calcium and tissue thromboplastin is added. This is used to assess which of the following pathway? 
Select and explain. 
A. Extrinsic, B. Intrinsic, C. Fibrinolytic, D. Common
A: Extrinsic
Answer: A: Extrinsic 
Explanation: Whenever we want to assess the Extrinsic or Intrinsic pathway, the sample that is taken is Platelet poor plasma sample. Assessment of EXTRINSIC PATHWAY - tissue thromboplastin is added along with calcium Intrinsic pathway - addition of Ca2+ along with negatively charged substance like Kaolin or Cephalin.