Okay, let's tackle this question. The scenario is a preterm infant born at 31 weeks via C-section. The symptoms include tachypnea, nasal flaring, and retractions, which are signs of respiratory distress. The chest X-ray findings—ground-glass appearance, air bronchograms, poor lung expansion—are classic for respiratory distress syndrome (RDS) due to surfactant deficiency.

The core concept here is neonatal respiratory distress syndrome. It's caused by a lack of pulmonary surfactant, which is common in preterm infants because their lungs haven't developed enough to produce sufficient surfactant. Surfactant reduces alveolar surface tension, preventing alveolar collapse. Without it, the lungs can't expand properly, leading to the symptoms and X-ray findings described.

The correct treatment would be surfactant replacement therapy. This is administered via endotracheal tube and is the standard of care for RDS. It helps improve oxygenation and reduce the need for mechanical ventilation.

Now, looking at the options (even though they're not listed here), the distractors might include things like antibiotics (for infection, which isn't indicated here), diuretics (which are not used in RDS), or perhaps CPAP or mechanical ventilation. But the best treatment is surfactant replacement. Also, other possibilities like CPAP are supportive but not the primary treatment. Surfactant is the main intervention to address the underlying cause.

Clinical pearls: Remember that RDS is common in preterm infants, especially before 34 weeks. Surfactant therapy is most effective when given early. Also, C-section delivery increases the risk because the infant doesn't experience the natural stress of labor, which can induce surfactant production.

**Core Concept**
Neonatal respiratory distress syndrome (RDS) results from surfactant deficiency in preterm infants, leading to alveolar collapse and impaired gas exchange. Surfactant replacement therapy is the cornerstone treatment for RDS.

**Why the Correct Answer is Right**
Surfactant replacement therapy directly addresses the pathophysiology of RDS by reducing alveolar surface tension, preventing atelectasis, and improving oxygenation. It is administered via endotracheal intubation and is most effective when given early in the clinical course. Preterm infants <34 weeks are at highest risk due to immature surfactant production. **Why Each Wrong Option is Incorrect** **Option A:** Antibiotics are indicated for suspected pneumonia, which is not supported by this clinical scenario. **Option B:** Diuretics are contraindicated in RDS as they worsen lung fluid balance and oxygenation. **Option C:** Continuous positive airway pressure (CPAP) provides supportive ventilation but does not treat the underlying surfactant deficiency. **Clinical Pearl / High-Yield Fact** Cesarean delivery without labor increases RDS risk due to absent endogenous corticosteroid surge. Surfactant therapy combined with CPAP or mechanical ventilation is the gold standard for management. **Correct Answer: C. Surfactant replacement therapy**

✓ Correct Answer: B. Surfactant administration and oxygen therapy