Which of the following factors shifts hemoglobin's oxygen affinity to the right?

Hemoglobin's affinity for oxygen is influenced by various factors, and a rightward shift in the oxygen-hemoglobin dissociation curve indicates a decrease in this affinity, allowing for more oxygen to be released to the tissues.

An increase in the concentration of 2,3-diphosphoglycerate (2,3 DPG) is one of the key factors that causes this rightward shift. 2,3 DPG binds to deoxygenated hemoglobin, stabilizing it, and promoting the release of oxygen. This is particularly significant in conditions where increased oxygen delivery to tissues is necessary, such as during strenuous exercise or at high altitudes.

In contrast to this effect, decreased body temperature and increased pH would shift the curve to the left, indicating an increased affinity for oxygen, which is not conducive to delivering oxygen to tissues effectively. Increased pCO2 also favors the release of oxygen, but the most direct and specific factor in this scenario is indeed the increased levels of 2,3 DPG, making it the correct choice for this question regarding a shift to the right in hemoglobin's oxygen affinity.