Which of the Following Is/are Major Mechanism(s) That Contribute to the Pulmonary

Which of the following is/are major mechanism(s) that contribute to the pulmonary hypertension commonly seen in a patient with a pulmonary embolism?
1) Decreased cross-section area of the pulmonary vascular system
2) Vasoconstriction induced by alveolar hypoxia
3) Reflexes from the aortic and carotid sinus baroreceptors
4) Vasoconstriction induced by humoral agents

A) 1
B) 2, 3
C) 1, 2, 4
D) 1, 2, 3, 4