Correct answer: B). Non-conscious
Breathing is the process of moving air inside the body in the form of oxygen and throwing out carbon dioxide out of the body by the lung in order to facilitate gaseous exchange within the internal organ of the body.
Breathing is the non-conscious process occurring inside the body which is controlled by the brain stem of the brain, which automatically regulates the process of breathing such as rate of breathing and depth of breathing depending upon the body's demand.
The command originate at brain stem which is connected to spinal cord. It used a sensor called chemoreceptor for regulation of breathing.
It detect chemicals substances, it it find chemical in the body it passes the it to the central nervous system which then send the data to the respiratory control center of the brain.