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 drug of choice for prompt relief of an ongoing attack of angina precipitated by exercise or emotional stress is: 
Select and explain. 
A. Propranolol, B. Verapamil, C. Sublingual nitroglycerin, D. Sublingual nifedipine
C: Sublingual nitroglycerin
Answer: C: Sublingual nitroglycerin 
Explanation: None