Which of the following statements is correct regarding neutral regulation of cardiac activity ?
A. The cardiac centre lies in medulla oblongata of brain
B. Sympathetic nerve fibres accelerate the rate of heart beat and parasympathetic nerve fibres retard the rate of heart beat
C. Sensory fibres extend from the receptors present in the walls of aortic arch, carotid sinuses and vena cava to the cardiovascular centre in medulla oblongata
D. all of these
