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
[{'content': 'A patient on warfarin sodium following myocardial infarction reports for an oral surgical procedure. Which one of the following Laboratory tests should be preferred to ascertain the fitness \nSelect and explain. \nA. Prothrornbin time, B. Tourniquet time, C. Clotting time, D. Bleeding time', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]