This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Nitroglycerine exes beneficial effects in classical angina pectoris primarily by: 
Select and explain. 
A. Increase in total coronary blood flow, B. Redistribution of coronary blood flow, C. Reduction of cardiac preload, D. Reduction of cardiac afterload
C: Reduction of cardiac preload
Answer: C: Reduction of cardiac preload 
Explanation: (Ref: KDT 6/e p523) Mechanism of action nitrates in classical angina is reduction in preload (due to venodilation) and in variant angina is coronary vasodilation.