Cilia is abundant in the:
Correct Answer: C
Rationale: The correct answer is C: Fallopian tube. Cilia are hair-like structures that line the fallopian tube to help move the egg from the ovary to the uterus. This movement is crucial for fertilization to occur. The other choices, A, B, and D, are incorrect because cilia are not typically abundant in the urinary tract, intestinal tract, or male reproductive ducts, respectively. These regions do not require the same kind of movement facilitated by cilia in the fallopian tube.