**Core Concept**
Physiological jaundice in newborns is a common condition characterized by elevated bilirubin levels due to the breakdown of red blood cells. It occurs when the liver is still maturing and unable to efficiently conjugate and excrete bilirubin, leading to its accumulation in the bloodstream.

**Why the Correct Answer is Right**
Bilirubin levels typically rise after birth due to the breakdown of red blood cells that are 120 days old or older. The liver starts to conjugate bilirubin and excrete it into the bile, but this process takes a few days to mature. Physiological jaundice usually peaks between 3-5 days of life and resolves by 7-10 days. The bilirubin levels are usually less than 15 mg/dL, and the condition is not associated with any underlying liver or hemolytic disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because jaundice in the first 24 hours of life is not physiological and may indicate an underlying hemolytic disease or liver dysfunction.
**Option B:** This option is incorrect because jaundice beyond 2 weeks of age may indicate an underlying liver or hemolytic disease, such as biliary atresia or hemoglobinopathies.
**Option C:** This option is incorrect because jaundice in the first day of life may be physiological, but it is not the typical peak time for physiological jaundice.

**Clinical Pearl / High-Yield Fact**
Physiological jaundice in newborns is a self-limiting condition that resolves on its own, but it is essential to monitor bilirubin levels to prevent kernicterus, a serious complication of high bilirubin levels.

**Correct Answer: C.**