Infant respiratory distress syndrome (IRDS) may be defined as the medical condition in which the amount of lung surfactant is reduced. This disease is also known as hyaline membrane disease.
The main function of the type II alveolar cells is the secretion of the surfactant. The deficiency of surfactant causes the alveoli membrane cling to each other and causes difficulty in inflation. Hence, type II alveolar cells are not fully developed and doing their job.
Thus, the correct answer is Type II alveolar cells.
