Excessive release of the pollutant carbon monoxide (CO) into the air may produce a condition in which oxygen supply in the human body decreases. What causes this condition?

(a) When inhaled into the human body CO is converted into carbon dioxide

(b) The inhaled CO destroys the chemical structure of haemoglobin

(c) The inhaled CO has much higher affinity for haemoglobin as compared to oxygen

(d) The inhaled CO adversely affects the respiratory centre in the brain