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: Gynaecology & Obstetrics
Definitive sign of pregnancy : 
Select and explain. 
A. Uterine souffle, B. Ballottement, C. Fetal hea sound, D. Amenorrhea
C: Fetal hea sound
Answer: C: Fetal hea sound 
Explanation: Fetal hea sound