The condition in which oxygen supply in the human body decreases due to excessive release of carbon monoxide (CO) into the air is caused by option 3. When inhaled, carbon monoxide has a much higher affinity for hemoglobin as compared to oxygen.

Hemoglobin is the molecule in red blood cells that carries oxygen from the lungs to the rest of the body. It has a strong affinity for oxygen, allowing it to bind to oxygen molecules and transport them throughout the body. However, carbon monoxide also has an affinity for hemoglobin, and when there is a high concentration of carbon monoxide in the air, it can compete with oxygen for binding to hemoglobin.

When carbon monoxide binds to hemoglobin, it forms carboxyhemoglobin, which is a stable compound that cannot carry oxygen. This means that less oxygen is able to bind to hemoglobin and be transported to the cells in the body, leading to a decrease in the oxygen supply. This can result in symptoms such as shortness of breath, dizziness, headaches, and in severe cases, suffocation or death.

It is important to note that option 1 (conversion of CO into CO2) is not correct because carbon monoxide does not get converted into carbon dioxide in the body