This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
Isometric relaxation is defined as 
Select and explain. 
A. Relaxation of both atria, B. Relaxation of both atria with all valves open, C. Relaxation of LV with mital and aortic valve closed, D. Relaxation of LV with mital and aortic valve open
C: Relaxation of LV with mital and aortic valve closed
Answer: C: Relaxation of LV with mital and aortic valve closed 
Explanation: Ans. (c) Relaxation of LV with mital and aortic valve closedRef: Ganong, 25th ed/p.541Isovolumetric relaxation#At the end of systole both the AV valves and semilunar valves are closed, pressure inside the ventricles falls even more without any change in volume(isovolumetric)