Which of the following represents a risk factor for developing pulmonary embolism?

Each of the listed factors contributes to the risk of developing pulmonary embolism (PE), making the option that includes all of them the most comprehensive choice.

Dehydration can lead to hypercoagulability, as it results in a higher concentration of clotting factors in the blood. This increases the risk of thrombosis, which is a precursor for PE.

The use of oral contraceptives has been associated with an increased risk of venous thromboembolism, particularly in women who smoke or have other risk factors such as obesity or a personal or family history of thrombotic events. Estrogen in hormonal contraceptives can promote clot formation.

Prolonged immobility is another significant risk factor for PE, as it can lead to venous stasis, which increases the likelihood of thrombus formation in the deep veins of the legs. When these clots dislodge, they can travel to the pulmonary arteries and cause a PE.

Considering these associations, all these factors are relevant and can independently or collectively increase the likelihood of pulmonary embolism, making the inclusive option the most accurate choice.