The first heart sound is produced by the________?
AOpening of the mitral and tricuspid valves
BOpening of the aortic and pulmonary valves
CClosure of the mitral and tricuspid valves
DClosure of the aortic and pulmonary valves
Correct answer
C. Closure of the mitral and tricuspid valves
Explanation
The correct answer is Closure of the mitral and tricuspid valves.