This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bleeding from the GUT and diseases of esophagus, Subject name: Medicine
The threshold for prophylactic platelet transfusion is __________platelets / mL. 
Select and explain. 
A. 5000, B. 10000, C. 15000, D. 50000
B: 10000
Answer: B: 10000 
Explanation: The threshold for prophylactic platelet transfusion is 10,000/mL. For invasive procedures, the target level is 50,000/mL. Note: Shelf life of donor platelets is 5 days.It is stored on a special agitator at 20-24 degC. The half-life of transfused platelets is 3-5 days. One unit of pooled platelets should be infused over a period of time less than 30 minutes because of the risk of bacterial proliferation.