Task: Question Answering
Input (English): Question: What is cardiac output? 
 Options:  <1> The volume of blood that leaves the heart per unit of time (ml / min or l / min). <2> The complete heartbeat constituted by contraction (systole) and relaxation (diastole) in both atria and in both ventricles measured in time (sec). <3> The blood that remains in the heart when the pressure gradient determines the distension of the cardiac fibers. <4> The power gradient of the contraction, also called contractility. <5> The ventricular volume that remains constant.
Output (English): 1