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: Surgery
Reactionary hemorrhage is hemorrhage after surgery that occurs 
Select and explain. 
A. Within 24 hours, B. After 24 hour, C. After 72 hours, D. After 7 days
A: Within 24 hours
Answer: A: Within 24 hours 
Explanation: None