**Core Concept**
In the first day of life, a newborn's body undergoes significant changes as it adapts to the external environment. Vomiting in the first 24 hours can be caused by various factors related to the transition from fetal to neonatal life. The primary concern is to identify the underlying cause, which may be physiological, pathological, or related to maternal factors.

**Why the Correct Answer is Right**
The correct answer includes conditions that are commonly associated with vomiting in the first day of life. Physiological jaundice, often seen in the first week, may cause vomiting due to the breakdown of red blood cells and bilirubin toxicity. Maternal factors such as maternal diabetes can cause polycythemia in the newborn, leading to increased viscosity of the blood and subsequent vomiting. Additionally, birth asphyxia can cause vomiting due to metabolic acidosis and hypoxia.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not directly relate to the first day of life. Gastroesophageal reflux disease (GERD) is more commonly seen in older infants and children.
**Option B:** This option is incorrect as pyloric stenosis typically presents after the first few weeks of life, not in the first day.
**Option C:** This option is incorrect as Hirschsprung's disease usually presents with constipation and abdominal distension, not vomiting in the first day.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that vomiting in the first day of life can be a sign of a more serious underlying condition, such as birth asphyxia or congenital anomalies. A thorough investigation, including maternal and newborn history, physical examination, and laboratory tests, is necessary to determine the cause.

**Correct Answer: D. Physiological jaundice, Maternal diabetes, Birth asphyxia**