The correct option is C Maintains the normal rate of heart beat
Artificial pacemaker is a medical device which is used for a person with blocked or dysfunctional sino-atrial node.
Sino-atrial node (SAN) is a patch of nodal tissue that is present in the right upper corner of the right atrium. It is considered as the pacemaker of the heart responsible for the conduction of impulse causing the contraction of the heart muscles. It is also responsible for regulating the rhythmic contraction of the heart.
When there is heart blockage or the natural pacemaker SA node stops functioning to its fullest capabilities, normal heart beat is restored and maintained using an artificial pacemaker.