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
Isovolumic relaxation phase of the cardiac cycle ends with 
Select and explain. 
A. Peak of 'C' waves, B. Opening of AV valve, C. Closure of semilunar valve, D. Beginning of 'T' wave
B: Opening of AV valve
Answer: B: Opening of AV valve 
Explanation: Cardiac cycle events
1.    AV valves open – 
a.     End of isovolumetric relaxation
b.    Start of rapid filling phase
c.     ECG- end of T wave
d.    JVP- Y wave (V-Y descent)
2.    AV valves closure-
a.     End of diastole
b.    Beginning of isovolumetric contraction
c.     ECG- R wave later half
d.    JVP- End of X descent
3.    Semilunar valves open
a.     End of isovolumetric contraction
b.    Ejection phase starts
c.     ECG- ST segment
d.    JVP- the peak of ‘c’ wave
4.    Semilunar valve closure
a.     Systole ends
b.    Isovolumetric relaxation starts
c.     ECG- T wave later half