**Core Concept**
Diffusion hypoxia is a condition that occurs when the lungs are exposed to high concentrations of nitrous oxide (N2O), a common inhalational anesthetic agent. This leads to the rapid diffusion of N2O from the bloodstream into the lungs, causing a decrease in the partial pressure of oxygen (pO2) in the alveoli, resulting in hypoxia.

**Why the Correct Answer is Right**
During the cessation of nitrous oxide administration, the rapid diffusion of N2O from the bloodstream into the lungs leads to a dilutional effect on the alveolar oxygen. This results in a decrease in the partial pressure of oxygen in the alveoli, causing hypoxia. The diffusion of N2O is facilitated by its high solubility in blood and tissues, allowing it to rapidly equilibrate with the alveolar gas.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because diffusion hypoxia is not typically associated with the administration of other inhalational anesthetic agents such as sevoflurane or desflurane.

**Option B:** This option is incorrect because diffusion hypoxia is not a direct result of the administration of oxygen (O2) itself, but rather the dilutional effect of N2O on the alveolar oxygen.

**Option C:** This option is incorrect because diffusion hypoxia is not a direct result of the administration of air or other gas mixtures.

**Clinical Pearl / High-Yield Fact**
To minimize the risk of diffusion hypoxia, it is essential to gradually reduce the concentration of nitrous oxide during the transition from anesthesia to spontaneous breathing. This allows for a more gradual equilibration of the alveolar gas and minimizes the risk of hypoxia.

**Correct Answer: D. Nitrous oxide administration**