Task: Question Answering
Input (English): Question: During ventricular systole: 
 Options:  <1> All ventricular blood is expelled. <2> Intraventricular pressure is equal in both ventricles. <3> The ventricular volume begins to decrease from the beginning of the contraction. <4> The atrio-ventricular valves are open. <5> The atria are relaxed.
Output (English): 5