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: Dental
Which of the following can lead to uncontrolled bleeding during oral prophylaxis 
Select and explain. 
A. Patient on Heparin, B. Patient on Nifedipine, C. Patient on phenytoin, D. None of the above
A: Patient on Heparin
Answer: A: Patient on Heparin 
Explanation: None