**Core Concept**
Physiological jaundice in newborns is a common condition characterized by elevated bilirubin levels due to the immaturity of the liver and the breakdown of red blood cells. It typically presents within the first week of life and resolves spontaneously within two weeks.

**Why the Correct Answer is Right**
Physiological jaundice is managed by phototherapy, which involves exposure to specific wavelengths of light that help break down bilirubin. This is the primary treatment for physiological jaundice, as it is effective and non-invasive. Additionally, hydration and breast milk feeding are also recommended to help manage the condition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a recommended treatment for physiological jaundice. While exchange transfusion is a treatment for severe hyperbilirubinemia, it is not necessary for physiological jaundice.
**Option B:** This option is incorrect because phenobarbital is not a standard treatment for physiological jaundice. While it can stimulate the liver to produce more enzymes, it is not typically used for this condition.
**Option C:** This option is incorrect because fomepizole is actually used to treat methanol or ethylene glycol poisoning, not physiological jaundice.

**Clinical Pearl / High-Yield Fact**
It is essential to note that physiological jaundice is a benign condition, and most cases resolve spontaneously. However, it is crucial to monitor bilirubin levels to prevent kernicterus, a serious complication of untreated hyperbilirubinemia.

**Correct Answer: A. Exchange transfusion.**