**Core Concept:** Apnoea is a brief cessation of breathing in infants, which can lead to hypoxia and acidosis if prolonged. In premature infants, apnoea is a common physiological phenomenon that occurs due to immaturity of the respiratory system.

**Why the Correct Answer is Right:** Premature infants have immature respiratory control systems, which can lead to brief episodes of apnoea. The correct answer, **C. 20-30 seconds**, represents the duration of typical apnoea events in premature infants. This range is generally considered physiological and does not require intervention.

**Why Each Wrong Option is Incorrect:**

A. **1-2 minutes (60-120 seconds)**: This duration is longer than the typical physiological apnoea events in premature infants and should prompt intervention.

B. **5-10 minutes (300-600 seconds)**: This duration is significantly longer than the typical physiological apnoea events and should also prompt intervention.

D. **Infants with severe respiratory distress syndrome (RDS)**: This option is unrelated to the duration of apnoea events in premature infants. The severity of respiratory distress syndrome does not define the duration of apnoea; rather, the duration of apnoea is determined based on the infant's age and maturity.

**Clinical Pearl / High-Yield Fact:** Monitoring and managing apnoea in premature infants is crucial to prevent hypoxia and acidosis. Neonatologists typically assess apnoea episodes based on duration, followed by the presence of bradycardia (slow heart rate) and meconium staining of meconium-stained amniotic fluid.

**Explanation:** Premature infants can experience physiological apnoea events due to immaturity of their respiratory control systems. These episodes are typically short, lasting 20-30 seconds, and are not associated with any interventions. In contrast, longer durations (60-120 seconds) would be considered abnormal and prompt further evaluation and intervention.

**Correct Answer:** C. 20-30 seconds.

**Wrong Options Explanation:**

A. Longer apnoea events (60-120 seconds) are typically abnormal and indicate a need for further evaluation and intervention.

B. Apnoea events lasting 5-10 minutes (300-600 seconds) are also considered abnormal and should prompt intervention.

D. The severity of respiratory distress syndrome (RDS) is unrelated to the duration of apnoea events in premature infants. The duration of apnoea events is determined by the infant's age and level of maturity, not the severity of respiratory distress syndrome.