During Mechanical Ventilation of a Preterm Neonate, Which of the Following

During mechanical ventilation of a preterm neonate, which of the following are considered to be important etiologic factors for the development of pulmonary air leak syndromes?
1) High levels of PEEP
2) High oxygen concentration
3) Prolonged inspiratory time
4) High PIP

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