**Core Concept**
The lactiferous ducts are a crucial part of the mammary gland, responsible for milk secretion and ejection during lactation. These ducts are tubular structures that originate from the terminal end of the mammary gland lobules and converge to form the lactiferous sinus before emptying onto the nipple surface.

**Why the Correct Answer is Right**
The lactiferous ducts play a vital role in the milk ejection reflex, allowing milk to be expressed from the breast. Each duct is lined with myoepithelial cells that contract to facilitate milk ejection. The lactiferous ducts converge to form the lactiferous sinus, which empties onto the nipple surface through a single opening called the nipple orifice. This unique arrangement allows for efficient milk expression and ejection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately represent the number of lactiferous ducts that open onto the nipple surface. While multiple ducts converge to form the lactiferous sinus, they ultimately empty onto the nipple through a single opening.
**Option B:** This option is incorrect because it suggests a different number of lactiferous ducts than the correct answer. The actual number of ducts that open onto the nipple surface is a key anatomical detail.
**Option C:** This option is incorrect because it implies a different arrangement of the lactiferous ducts than the correct answer. The lactiferous ducts do not open onto the nipple surface in multiple locations.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the lactiferous ducts converge to form the lactiferous sinus, which empties onto the nipple surface through a single opening. This unique arrangement allows for efficient milk expression and ejection during lactation.

**Correct Answer: 15. Fifteen lactiferous ducts open in the nipple.**