Carbon monoxide (CO), an air pollutant when inhaled readily binds with the hemoglobin in the blood stream to form a life threatering compound known as

The correct option is Carboxy hemoglobin.

Step-by-step Explanation:
1. Role of Hemoglobin: Hemoglobin is the iron-containing oxygen-transport metalloprotein in red blood cells. Its primary function is to bind oxygen (O₂) in the lungs and release it in the tissues that require it.
2. Carbon Monoxide Affinity: Carbon monoxide (CO) is a colorless, odorless, and tasteless toxic gas. When inhaled, it competes with oxygen to bind to the same active sites (iron atoms) on the hemoglobin molecule. Hemoglobin has an affinity for carbon monoxide that is approximately 200 to 250 times greater than its affinity for oxygen.
3. Formation of the Complex: Because of this extremely high binding affinity, carbon monoxide readily displaces oxygen and binds with hemoglobin to form a highly stable coordination complex. This specific compound is called carboxyhemoglobin (or carboxy hemoglobin).
4. Mechanism of Toxicity: The formation of carboxyhemoglobin reduces the oxygen-carrying capacity of the blood in two ways: it directly blocks oxygen from binding, and it alters the structure of hemoglobin so that any remaining bound oxygen cannot be easily released to body tissues. This leads to cellular hypoxia (oxygen starvation) and can be fatal.

We can represent this chemical binding process as follows:

$$\text{Hb (Hemoglobin)}+\text{CO (Carbon Monoxide)}\to \text{HbCO (Carboxyhemoglobin)}$$

Comparison with other options:
• Carbo hemoglobin: Often confused with carbaminohemoglobin, which is the compound formed when carbon dioxide (CO₂) binds to the amino groups of hemoglobin (not carbon monoxide).
• Carbon mono hemoglobin and Hemoglobous: These are incorrect and scientifically non-existent terms.