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
True regarding estimation of Prothrombin time is: 
Select and explain. 
A. Immediately refrigerate to preserve factor bility, B. Platelet rich plasma is essential, C. Run the test within 2 hours, D. Activated with Kaolin
C: Run the test within 2 hours
Answer: C: Run the test within 2 hours 
Explanation: . Run the test within 2 hours