Final answer:
Decrease of alveolar PO2 would most likely increase hypoxic pulmonary vasoconstriction, directing blood from poorly ventilated to well-ventilated lung areas.
Step-by-step explanation:
The intervention that would most likely increase hypoxic pulmonary vasoconstriction is B. Decrease of alveolar PO2. Hypoxic pulmonary vasoconstriction is a mechanism by which the small pulmonary arteries and arterioles constrict in response to low oxygen levels (hypoxia) in the surrounding alveoli. This physiological response serves to redirect blood flow from poorly ventilated areas of the lung to well-ventilated regions, optimizing gas exchange. If alveolar PO2 decreases, this signals a lack of sufficient oxygen in that alveolar region and therefore triggers vasoconstriction to divert blood to better oxygenated areas of the lung.