Respiratory Causes of Persistent Pulmonary Hypertension of the Newborn (PPHN)

Respiratory causes of persistent pulmonary hypertension of the newborn (PPHN) include:
1) congenital heart disease.
2) hypoxia.
3) meconium aspiration syndrome (MAS) .
4) respiratory distress syndrome (RDS) .

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