How carbon monoxide, emitted by automobiles, prevents transport of oxygen in the body tissues

Q. How carbon monoxide, emitted by automobiles, prevents transport of oxygen in the body tissues

1. By chaning oxygen into carbon dioxide
2. By destroying the haemoglobin
3. By forming a stable compound with haemoglobin
4. By obstructing the reaction of oxygen with haemoglobin

Answer: By forming a stable compound with haemoglobin