The correct option is D Low O2 and high CO2 concentration
The amount of oxygen bound to the haemoglobin is related to the partial pressure of oxygen to which the haemoglobin is exposed. In the lungs, at the alveolar-capillary interface, the partial pressure of oxygen is typically high, and therefore the oxygen binds readily to haemoglobin that is present. As the blood circulates to other body tissue in which the partial pressure of oxygen is less, the haemoglobin releases the oxygen into the tissue because the haemoglobin cannot maintain its full bound capacity of oxygen in the presence of lower oxygen partial pressures. The effectiveness of haemoglobin-oxygen binding can be affected by several factors. The standard curve is shifted to the right by an increase in temperature, 2,3-DPG, or PCO2, or a decrease in pH. The curve is shifted to the left by the opposite of these conditions. A rightward shift causes a decrease in the affinity of haemoglobin for oxygen. This makes it easier for the haemoglobin to release bound oxygen. Conversely, a leftward shift increases the affinity, making the oxygen easier for the haemoglobin to pick up but harder to release.