A yound infant may be feeding entirely on mother's milk which is white in colour but the stools which the infant passes out is quite yellowish. The yellow colour of stool is due to

Options

A. bile pigments passed through bile juice
B. undigested milk protein casein
C. pancreatic juice poured into duodenum
D. intestinal juice.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Composition of Mother's Milk:**
- Mother's milk is primarily composed of water, fats, proteins, lactose (a sugar), vitamins, and minerals. It is typically white in color.

2. **Observing the Stool Color:**
- Despite the white color of the mother's milk, the stools of the infant are yellowish in color. This prompts the question of why this color change occurs.

3. **Identifying the Source of Stool Color:**
- The yellow color of the stool in infants is primarily due to the presence of bile pigments. Bile pigments are waste products formed from the breakdown of hemoglobin in red blood cells.

4. **Understanding Bile Production:**
- Bile is produced by the liver and contains two main pigments: bilirubin (yellow) and biliverdin (green). These pigments are responsible for the coloration of bile.

5. **Bile Storage and Secretion:**
- After production, bile is stored in the gallbladder. When food enters the duodenum (the first part of the small intestine), bile is secreted from the gallbladder into the duodenum to aid in digestion.

6. **Role of Bile in Digestion:**
- Bile helps emulsify fats, making them easier to digest and absorb. The presence of bile pigments in the digestive system contributes to the yellowish color of the stool as they are excreted.

7. **Conclusion:**
- Therefore, the yellowish color of the infant's stool is due to the presence of bile pigments that are excreted through bile juices.

**Final Answer:**
The yellow color of the stool is due to the presence of bile pigments.

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