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: Physiology
At the end of isovolumetric relaxation phase 
Select and explain. 
A. Atrioventricular valve opens, B. Atrioventricular valve close, C. Corresponds to peak of C wave in JVP, D. Corresponds to T wave in ECG
A: Atrioventricular valve opens
Answer: A: Atrioventricular valve opens 
Explanation: None