Final answer:
The correct answer to the student's question is the infundibulum, which is the expanded, initial segment of the uterine tube.
Step-by-step explanation:
The expanded, initial segment of the uterine tube is called the infundibulum. The infundibulum is a funnel-shaped opening near the ovary with finger-like projections called fimbriae, which help in capturing the released ovum (egg) during ovulation. While the terms fimbria, tunnel, ampulla, and os are related to the reproductive system, the correct term for the expanded initial segment of the uterine tube is infundibulum (Answer B).