**Core Concept**
Pulmonary surfactant is a complex mixture of lipids and proteins that reduces surface tension in the alveoli, facilitating lung expansion during breathing. In premature infants, the deficiency of surfactant leads to respiratory distress syndrome (RDS) due to increased alveolar collapse and difficulty in maintaining lung volume.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of respiratory distress syndrome in premature infants. Surfactant deficiency disrupts the normal functioning of type II pneumocytes, which are responsible for producing and secreting surfactant into the alveoli. This disruption leads to increased surface tension, making it difficult for the lungs to expand and maintain their volume, resulting in RDS.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because surfactant deficiency is not directly related to the absence of surfactant proteins, but rather an imbalance between the production and degradation of surfactant components.
**Option B:** This option is incorrect because surfactant is not produced in the bronchioles, but rather in the type II pneumocytes of the alveoli.
**Option C:** This option is incorrect because surfactant deficiency does not lead to an increase in surfactant production, but rather a decrease due to the immaturity of the fetal lung.

**Clinical Pearl / High-Yield Fact**
Premature infants with respiratory distress syndrome can be treated with exogenous surfactant administration, which has significantly improved their survival rates.

**Correct Answer: D. Surfactant deficiency in premature infants is due to the immaturity of type II pneumocytes, which are unable to produce sufficient surfactant to reduce alveolar surface tension.**