The correct option is D Carbon monoxide
Carbon monoxide mainly causes adverse effects in humans by combining with hemoglobin to form carboxyhaemoglobin (HbCO) in the blood. This prevents haemoglobin from carrying oxygen to the tissues, effectively reducing the oxygen-carrying capacity of the blood, leading to hypoxia. The compound HbCO is highly stable in nature so it takes longer time to recover back to normal state.