**Core Concept**
Phototherapy is a standard treatment for neonatal jaundice, especially in preterm infants, to prevent kernicterus and promote bilirubin excretion. However, in extremely low birth weight (ELBW) infants, the risks associated with phototherapy must be weighed against its benefits.

**Why the Correct Answer is Right**
In ELBW infants, the skin is highly permeable, and phototherapy can cause a significant loss of water and electrolytes, potentially leading to dehydration and electrolyte imbalance. Therefore, in such cases, the ideal management would be to use a combination of phototherapy and exchange transfusion to rapidly reduce bilirubin levels while minimizing the risks associated with phototherapy.

**Why Each Wrong Option is Incorrect**
* **Option A:** Phototherapy alone would be insufficient to rapidly reduce bilirubin levels in ELBW infants and may lead to dehydration and electrolyte imbalance.
* **Option B:** Exchange transfusion alone would be too invasive and may not be necessary in this case, given the relatively low bilirubin levels.
* **Option D:** No treatment would be inappropriate, as high bilirubin levels in ELBW infants can lead to kernicterus and long-term neurological damage.

**Clinical Pearl / High-Yield Fact**
In ELBW infants, close monitoring of bilirubin levels, electrolytes, and fluid status is crucial to prevent complications associated with phototherapy.

**Correct Answer: C.**