This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
A 75-year-old woman is admitted to the hospital with anginal pain. ECG reveals myocardial infarction and a right bundle branch block. During physical examination the patient has a loud second heart sound. Which of the following heart valves are responsible for the production of the second heart sound? 
Select and explain. 
A. Aortic and pulmonary, B. Aortic and tricuspid, C. Tricuspid and mitral, D. Mitral and pulmonary
A: Aortic and pulmonary
Answer: A: Aortic and pulmonary 
Explanation: The second heart sound is caused by the closure of the aortic and pulmonary valves. The first sound by the heart is caused by the closure of the tricuspid and mitral valves.