<prompt> Pacemaker regulating the rate of respirationPneumotaxic centreDorpal group of nucleusApneustic centrePre-Botzinger complex  <response>: The pre-Botzinger complex preBotC is a cluster of interneurons in the ventral respiratory group of the medulla of the brainstem. This complex has been proven to be essential for the generation of the respiratory rhythm in mammals Ref: guyton and hall textbook of medical physiology 12 edition page number:370,371,372 