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: Physiology
Prothrombin time is useful for 
Select and explain. 
A. Detection of clot retraction, B. Platelet count, C. In hemophilia, D. For evaluation in a patient taking anticoagulant drugs
D: For evaluation in a patient taking anticoagulant drugs
Answer: D: For evaluation in a patient taking anticoagulant drugs 
Explanation: None