There are absent p waves and this is a sign that there is a problem with the atrium. The pacemaker should be applied in the atrioventricular also known as AV node. As per the given, the qrs and the t waves are normal.
This means the depolarization and repolarization should be done in a normal manner which can only be done if option B is chosen. Placing the pacemaker in the Purkinje system would make the ventricles become activated in an abnormal sequence. This should be avoided because even the qrs would follow an abnormal sequence.
Atrioventricular (av) node-the absent p wave indicates that the atrium is not depolarizing and,
therefore, the pacemaker cannot be in the sinoatrial (sa) node. because the qrs and t waves
are normal, depolarization and repolarization of the ventricle must be proceeding in the normal
sequence. this situation can occur if the pacemaker is located in the atrioventricular (av) node.
if the pacemaker were located in the bundle of his or in the purkinje system, the ventricles would
activate in an abnormal sequence (depending on the exact location of the pacemaker) and the
qrs wave would have an abnormal configuration. ventricular muscle does not have pacemaker