The correct option is B Heart
Bundle of His is a network of cardiac muscle fibres found only in the ventricle wall. The bundle of His in continuation of the AV node gives off a left bundle branch at the top of the interventricular septum and continues as the right bundle branch. It is a part of conducting system along with the other parts like SA node, internodal atrial pathways, atrioventricular node, Purkinje system.
SA node -> Impulse -> Artrial pathways -> AV node -> bundle of His ->purkinje system - >ventricular muscle.