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
Best way to monitor perfusion of free flap: 
Select and explain. 
A. Pulse oximeter, B. Laser doppler velocimetery, C. Prick test, D. Flourescin & dermo flourometer
C: Prick test
Answer: C: Prick test 
Explanation: None