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: Medicine
The following agents may be used as prophylaxis in high altitude pulmonary edema - 
Select and explain. 
A. ACE inhibitor, B. Acetazolamide, C. Nifedipine, D. Digoxin
C: Nifedipine
Answer: C: Nifedipine 
Explanation: None