This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
A 20 year old lady had a full term normal delivery 3 days ago. She complains of breast engorgement and swelling in regions at about the level of the umbilicus and at the lateral abdomen. There seems to be some leaking from these areas of swelling. Which of the following is the most likely diagnosis? 
Select and explain. 
A. Hyperprolactinemia, B. Accessory breast tissue, C. Ascites, D. Cutaneous malignancy
B: Accessory breast tissue
Answer: B: Accessory breast tissue 
Explanation: These areas likely are accessory breast tissue. The "milk line" extends from the axilla to the groin area, and accessory mammary tissue may be present anywhere along this line. The mammary glands of the breasts develop embryologically as invaginations of surface ectoderm along two ventral lines, the milk lines, from the axillae to the groin. Extra nipples could also grow along the "milk line".